Python之路【第二篇】:Python基础(一)

 

入门知识拾遗

一、作用域

对于变量的作用域,执行声明并在内存中存在,该变量就可以在下面的代码中使用。

if 1==1:
name = 'JasonWang'
print name

下面的结论对吗?

外层变量,可以被内层变量使用
内层变量,无法被外层变量使用

二、三元运算

result = 值1 if 条件 else 值2
#三目运算符
name = 'aa' if 1 == 2 else 'SB'
print(name)
SB

如果条件为真:result = 值1
如果条件为假:result = 值2

三、进制

  • 二进制,01
  • 八进制,01234567
  • 十进制,0123456789
  • 十六进制,0123456789ABCDEF

Python基础

对于Python,一切事物都是对象,对象基于类创建

所以,以下这些值都是对象: "wupeiqi"、38、['北京', '上海', '深圳'],并且是根据不同的类生成的对象。

一、整数

如: 18、73、84

每一个整数都具备如下功能:

lass int(object):
"""
int(x=0) -> int or long
int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments
are given. If x is floating point, the conversion truncates towards zero.
If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or
Unicode object representing an integer literal in the given base. The
literal can be preceded by '+' or '-' and be surrounded by whitespace.
The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to
interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
4
"""
def bit_length(self):
""" 返回表示该数字的时占用的最少位数 """
"""
int.bit_length() -> int Number of bits necessary to represent self in binary.
>>> bin(37)
'0b100101'
>>> (37).bit_length()
6
"""
return 0 def conjugate(self, *args, **kwargs): # real signature unknown
""" 返回该复数的共轭复数 """
""" Returns self, the complex conjugate of any int. """
pass def __abs__(self):
""" 返回绝对值 """
""" x.__abs__() <==> abs(x) """
pass def __add__(self, y):
""" x.__add__(y) <==> x+y """
pass def __and__(self, y):
""" x.__and__(y) <==> x&y """
pass def __cmp__(self, y):
""" 比较两个数大小 """
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __coerce__(self, y):
""" 强制生成一个元组 """
""" x.__coerce__(y) <==> coerce(x, y) """
pass def __divmod__(self, y):
""" 相除,得到商和余数组成的元组 """
""" x.__divmod__(y) <==> divmod(x, y) """
pass def __div__(self, y):
""" x.__div__(y) <==> x/y """
pass def __float__(self):
""" 转换为浮点类型 """
""" x.__float__() <==> float(x) """
pass def __floordiv__(self, y):
""" x.__floordiv__(y) <==> x//y """
pass def __format__(self, *args, **kwargs): # real signature unknown
pass def __getattribute__(self, name):
""" x.__getattribute__('name') <==> x.name """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
""" 内部调用 __new__方法或创建对象时传入参数使用 """
pass def __hash__(self):
"""如果对象object为哈希表类型,返回对象object的哈希值。哈希值为整数。在字典查找中,哈希值用于快速比较字典的键。两个数值如果相等,则哈希值也相等。"""
""" x.__hash__() <==> hash(x) """
pass def __hex__(self):
""" 返回当前数的 十六进制 表示 """
""" x.__hex__() <==> hex(x) """
pass def __index__(self):
""" 用于切片,数字无意义 """
""" x[y:z] <==> x[y.__index__():z.__index__()] """
pass def __init__(self, x, base=10): # known special case of int.__init__
""" 构造方法,执行 x = 123 或 x = int(10) 时,自动调用,暂时忽略 """
"""
int(x=0) -> int or long
int(x, base=10) -> int or long Convert a number or string to an integer, or return 0 if no arguments
are given. If x is floating point, the conversion truncates towards zero.
If x is outside the integer range, the function returns a long instead. If x is not a number or if base is given, then x must be a string or
Unicode object representing an integer literal in the given base. The
literal can be preceded by '+' or '-' and be surrounded by whitespace.
The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to
interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
4
# (copied from class doc)
"""
pass def __int__(self):
""" 转换为整数 """
""" x.__int__() <==> int(x) """
pass def __invert__(self):
""" x.__invert__() <==> ~x """
pass def __long__(self):
""" 转换为长整数 """
""" x.__long__() <==> long(x) """
pass def __lshift__(self, y):
""" x.__lshift__(y) <==> x<<y """
pass def __mod__(self, y):
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, y):
""" x.__mul__(y) <==> x*y """
pass def __neg__(self):
""" x.__neg__() <==> -x """
pass @staticmethod # known case of __new__
def __new__(S, *more):
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __nonzero__(self):
""" x.__nonzero__() <==> x != 0 """
pass def __oct__(self):
""" 返回改值的 八进制 表示 """
""" x.__oct__() <==> oct(x) """
pass def __or__(self, y):
""" x.__or__(y) <==> x|y """
pass def __pos__(self):
""" x.__pos__() <==> +x """
pass def __pow__(self, y, z=None):
""" 幂,次方 """
""" x.__pow__(y[, z]) <==> pow(x, y[, z]) """
pass def __radd__(self, y):
""" x.__radd__(y) <==> y+x """
pass def __rand__(self, y):
""" x.__rand__(y) <==> y&x """
pass def __rdivmod__(self, y):
""" x.__rdivmod__(y) <==> divmod(y, x) """
pass def __rdiv__(self, y):
""" x.__rdiv__(y) <==> y/x """
pass def __repr__(self):
"""转化为解释器可读取的形式 """
""" x.__repr__() <==> repr(x) """
pass def __str__(self):
"""转换为人阅读的形式,如果没有适于人阅读的解释形式的话,则返回解释器课阅读的形式"""
""" x.__str__() <==> str(x) """
pass def __rfloordiv__(self, y):
""" x.__rfloordiv__(y) <==> y//x """
pass def __rlshift__(self, y):
""" x.__rlshift__(y) <==> y<<x """
pass def __rmod__(self, y):
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, y):
""" x.__rmul__(y) <==> y*x """
pass def __ror__(self, y):
""" x.__ror__(y) <==> y|x """
pass def __rpow__(self, x, z=None):
""" y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
pass def __rrshift__(self, y):
""" x.__rrshift__(y) <==> y>>x """
pass def __rshift__(self, y):
""" x.__rshift__(y) <==> x>>y """
pass def __rsub__(self, y):
""" x.__rsub__(y) <==> y-x """
pass def __rtruediv__(self, y):
""" x.__rtruediv__(y) <==> y/x """
pass def __rxor__(self, y):
""" x.__rxor__(y) <==> y^x """
pass def __sub__(self, y):
""" x.__sub__(y) <==> x-y """
pass def __truediv__(self, y):
""" x.__truediv__(y) <==> x/y """
pass def __trunc__(self, *args, **kwargs):
""" 返回数值被截取为整形的值,在整形中无意义 """
pass def __xor__(self, y):
""" x.__xor__(y) <==> x^y """
pass denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 分母 = 1 """
"""the denominator of a rational number in lowest terms""" imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 虚数,无意义 """
"""the imaginary part of a complex number""" numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 分子 = 数字大小 """
"""the numerator of a rational number in lowest terms""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
""" 实属,无意义 """
"""the real part of a complex number"""

int

二、长整型

可能如:2147483649、9223372036854775807

每个长整型都具备如下功能:

 class long(object):
"""
long(x=0) -> long
long(x, base=10) -> long Convert a number or string to a long integer, or return 0L if no arguments
are given. If x is floating point, the conversion truncates towards zero. If x is not a number or if base is given, then x must be a string or
Unicode object representing an integer literal in the given base. The
literal can be preceded by '+' or '-' and be surrounded by whitespace.
The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to
interpret the base from the string as an integer literal.
>>> int('0b100', base=0)
4L
"""
def bit_length(self): # real signature unknown; restored from __doc__
"""
long.bit_length() -> int or long Number of bits necessary to represent self in binary.
>>> bin(37L)
'0b100101'
>>> (37L).bit_length()
"""
return 0 def conjugate(self, *args, **kwargs): # real signature unknown
""" Returns self, the complex conjugate of any long. """
pass def __abs__(self): # real signature unknown; restored from __doc__
""" x.__abs__() <==> abs(x) """
pass def __add__(self, y): # real signature unknown; restored from __doc__
""" x.__add__(y) <==> x+y """
pass def __and__(self, y): # real signature unknown; restored from __doc__
""" x.__and__(y) <==> x&y """
pass def __cmp__(self, y): # real signature unknown; restored from __doc__
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __coerce__(self, y): # real signature unknown; restored from __doc__
""" x.__coerce__(y) <==> coerce(x, y) """
pass def __divmod__(self, y): # real signature unknown; restored from __doc__
""" x.__divmod__(y) <==> divmod(x, y) """
pass def __div__(self, y): # real signature unknown; restored from __doc__
""" x.__div__(y) <==> x/y """
pass def __float__(self): # real signature unknown; restored from __doc__
""" x.__float__() <==> float(x) """
pass def __floordiv__(self, y): # real signature unknown; restored from __doc__
""" x.__floordiv__(y) <==> x//y """
pass def __format__(self, *args, **kwargs): # real signature unknown
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass def __hash__(self): # real signature unknown; restored from __doc__
""" x.__hash__() <==> hash(x) """
pass def __hex__(self): # real signature unknown; restored from __doc__
""" x.__hex__() <==> hex(x) """
pass def __index__(self): # real signature unknown; restored from __doc__
""" x[y:z] <==> x[y.__index__():z.__index__()] """
pass def __init__(self, x=0): # real signature unknown; restored from __doc__
pass def __int__(self): # real signature unknown; restored from __doc__
""" x.__int__() <==> int(x) """
pass def __invert__(self): # real signature unknown; restored from __doc__
""" x.__invert__() <==> ~x """
pass def __long__(self): # real signature unknown; restored from __doc__
""" x.__long__() <==> long(x) """
pass def __lshift__(self, y): # real signature unknown; restored from __doc__
""" x.__lshift__(y) <==> x<<y """
pass def __mod__(self, y): # real signature unknown; restored from __doc__
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, y): # real signature unknown; restored from __doc__
""" x.__mul__(y) <==> x*y """
pass def __neg__(self): # real signature unknown; restored from __doc__
""" x.__neg__() <==> -x """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __nonzero__(self): # real signature unknown; restored from __doc__
""" x.__nonzero__() <==> x != 0 """
pass def __oct__(self): # real signature unknown; restored from __doc__
""" x.__oct__() <==> oct(x) """
pass def __or__(self, y): # real signature unknown; restored from __doc__
""" x.__or__(y) <==> x|y """
pass def __pos__(self): # real signature unknown; restored from __doc__
""" x.__pos__() <==> +x """
pass def __pow__(self, y, z=None): # real signature unknown; restored from __doc__
""" x.__pow__(y[, z]) <==> pow(x, y[, z]) """
pass def __radd__(self, y): # real signature unknown; restored from __doc__
""" x.__radd__(y) <==> y+x """
pass def __rand__(self, y): # real signature unknown; restored from __doc__
""" x.__rand__(y) <==> y&x """
pass def __rdivmod__(self, y): # real signature unknown; restored from __doc__
""" x.__rdivmod__(y) <==> divmod(y, x) """
pass def __rdiv__(self, y): # real signature unknown; restored from __doc__
""" x.__rdiv__(y) <==> y/x """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __rfloordiv__(self, y): # real signature unknown; restored from __doc__
""" x.__rfloordiv__(y) <==> y//x """
pass def __rlshift__(self, y): # real signature unknown; restored from __doc__
""" x.__rlshift__(y) <==> y<<x """
pass def __rmod__(self, y): # real signature unknown; restored from __doc__
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, y): # real signature unknown; restored from __doc__
""" x.__rmul__(y) <==> y*x """
pass def __ror__(self, y): # real signature unknown; restored from __doc__
""" x.__ror__(y) <==> y|x """
pass def __rpow__(self, x, z=None): # real signature unknown; restored from __doc__
""" y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
pass def __rrshift__(self, y): # real signature unknown; restored from __doc__
""" x.__rrshift__(y) <==> y>>x """
pass def __rshift__(self, y): # real signature unknown; restored from __doc__
""" x.__rshift__(y) <==> x>>y """
pass def __rsub__(self, y): # real signature unknown; restored from __doc__
""" x.__rsub__(y) <==> y-x """
pass def __rtruediv__(self, y): # real signature unknown; restored from __doc__
""" x.__rtruediv__(y) <==> y/x """
pass def __rxor__(self, y): # real signature unknown; restored from __doc__
""" x.__rxor__(y) <==> y^x """
pass def __sizeof__(self, *args, **kwargs): # real signature unknown
""" Returns size in memory, in bytes """
pass def __str__(self): # real signature unknown; restored from __doc__
""" x.__str__() <==> str(x) """
pass def __sub__(self, y): # real signature unknown; restored from __doc__
""" x.__sub__(y) <==> x-y """
pass def __truediv__(self, y): # real signature unknown; restored from __doc__
""" x.__truediv__(y) <==> x/y """
pass def __trunc__(self, *args, **kwargs): # real signature unknown
""" Truncating an Integral returns itself. """
pass def __xor__(self, y): # real signature unknown; restored from __doc__
""" x.__xor__(y) <==> x^y """
pass denominator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the denominator of a rational number in lowest terms""" imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the imaginary part of a complex number""" numerator = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the numerator of a rational number in lowest terms""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the real part of a complex number""" long

long

三、浮点型

如:3.14、2.88

每个浮点型都具备如下功能:

 class float(object):
"""
float(x) -> floating point number Convert a string or number to a floating point number, if possible.
"""
def as_integer_ratio(self):
""" 获取改值的最简比 """
"""
float.as_integer_ratio() -> (int, int) Return a pair of integers, whose ratio is exactly equal to the original
float and with a positive denominator.
Raise OverflowError on infinities and a ValueError on NaNs. >>> (10.0).as_integer_ratio()
(10, 1)
>>> (0.0).as_integer_ratio()
(0, 1)
>>> (-.25).as_integer_ratio()
(-1, 4)
"""
pass def conjugate(self, *args, **kwargs): # real signature unknown
""" Return self, the complex conjugate of any float. """
pass def fromhex(self, string):
""" 将十六进制字符串转换成浮点型 """
"""
float.fromhex(string) -> float Create a floating-point number from a hexadecimal string.
>>> float.fromhex('0x1.ffffp10')
2047.984375
>>> float.fromhex('-0x1p-1074')
-4.9406564584124654e-324
"""
return 0.0 def hex(self):
""" 返回当前值的 16 进制表示 """
"""
float.hex() -> string Return a hexadecimal representation of a floating-point number.
>>> (-0.1).hex()
'-0x1.999999999999ap-4'
>>> 3.14159.hex()
'0x1.921f9f01b866ep+1'
"""
return "" def is_integer(self, *args, **kwargs): # real signature unknown
""" Return True if the float is an integer. """
pass def __abs__(self):
""" x.__abs__() <==> abs(x) """
pass def __add__(self, y):
""" x.__add__(y) <==> x+y """
pass def __coerce__(self, y):
""" x.__coerce__(y) <==> coerce(x, y) """
pass def __divmod__(self, y):
""" x.__divmod__(y) <==> divmod(x, y) """
pass def __div__(self, y):
""" x.__div__(y) <==> x/y """
pass def __eq__(self, y):
""" x.__eq__(y) <==> x==y """
pass def __float__(self):
""" x.__float__() <==> float(x) """
pass def __floordiv__(self, y):
""" x.__floordiv__(y) <==> x//y """
pass def __format__(self, format_spec):
"""
float.__format__(format_spec) -> string Formats the float according to format_spec.
"""
return "" def __getattribute__(self, name):
""" x.__getattribute__('name') <==> x.name """
pass def __getformat__(self, typestr):
"""
float.__getformat__(typestr) -> string You probably don't want to use this function. It exists mainly to be
used in Python's test suite. typestr must be 'double' or 'float'. This function returns whichever of
'unknown', 'IEEE, big-endian' or 'IEEE, little-endian' best describes the
format of floating point numbers used by the C type named by typestr.
"""
return "" def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass def __ge__(self, y):
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y):
""" x.__gt__(y) <==> x>y """
pass def __hash__(self):
""" x.__hash__() <==> hash(x) """
pass def __init__(self, x):
pass def __int__(self):
""" x.__int__() <==> int(x) """
pass def __le__(self, y):
""" x.__le__(y) <==> x<=y """
pass def __long__(self):
""" x.__long__() <==> long(x) """
pass def __lt__(self, y):
""" x.__lt__(y) <==> x<y """
pass def __mod__(self, y):
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, y):
""" x.__mul__(y) <==> x*y """
pass def __neg__(self):
""" x.__neg__() <==> -x """
pass @staticmethod # known case of __new__
def __new__(S, *more):
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y):
""" x.__ne__(y) <==> x!=y """
pass def __nonzero__(self):
""" x.__nonzero__() <==> x != 0 """
pass def __pos__(self):
""" x.__pos__() <==> +x """
pass def __pow__(self, y, z=None):
""" x.__pow__(y[, z]) <==> pow(x, y[, z]) """
pass def __radd__(self, y):
""" x.__radd__(y) <==> y+x """
pass def __rdivmod__(self, y):
""" x.__rdivmod__(y) <==> divmod(y, x) """
pass def __rdiv__(self, y):
""" x.__rdiv__(y) <==> y/x """
pass def __repr__(self):
""" x.__repr__() <==> repr(x) """
pass def __rfloordiv__(self, y):
""" x.__rfloordiv__(y) <==> y//x """
pass def __rmod__(self, y):
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, y):
""" x.__rmul__(y) <==> y*x """
pass def __rpow__(self, x, z=None):
""" y.__rpow__(x[, z]) <==> pow(x, y[, z]) """
pass def __rsub__(self, y):
""" x.__rsub__(y) <==> y-x """
pass def __rtruediv__(self, y):
""" x.__rtruediv__(y) <==> y/x """
pass def __setformat__(self, typestr, fmt):
"""
float.__setformat__(typestr, fmt) -> None You probably don't want to use this function. It exists mainly to be
used in Python's test suite. typestr must be 'double' or 'float'. fmt must be one of 'unknown',
'IEEE, big-endian' or 'IEEE, little-endian', and in addition can only be
one of the latter two if it appears to match the underlying C reality. Override the automatic determination of C-level floating point type.
This affects how floats are converted to and from binary strings.
"""
pass def __str__(self):
""" x.__str__() <==> str(x) """
pass def __sub__(self, y):
""" x.__sub__(y) <==> x-y """
pass def __truediv__(self, y):
""" x.__truediv__(y) <==> x/y """
pass def __trunc__(self, *args, **kwargs): # real signature unknown
""" Return the Integral closest to x between 0 and x. """
pass imag = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the imaginary part of a complex number""" real = property(lambda self: object(), lambda self, v: None, lambda self: None) # default
"""the real part of a complex number""" float

float

四、字符串

如:'Jim'、'Jade'

每个字符串都具备如下功能:

 class str(basestring):
"""
str(object='') -> string Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
"""
def capitalize(self):
""" 首字母变大写 """
"""
S.capitalize() -> string Return a copy of the string S with only its first character
capitalized.
"""
return "" def center(self, width, fillchar=None):
""" 内容居中,width:总长度;fillchar:空白处填充内容,默认无 """
"""
S.center(width[, fillchar]) -> string Return S centered in a string of length width. Padding is
done using the specified fill character (default is a space)
"""
return "" def count(self, sub, start=None, end=None):
""" 子序列个数 """
"""
S.count(sub[, start[, end]]) -> int Return the number of non-overlapping occurrences of substring sub in
string S[start:end]. Optional arguments start and end are interpreted
as in slice notation.
"""
return 0 def decode(self, encoding=None, errors=None):
""" 解码 """
"""
S.decode([encoding[,errors]]) -> object Decodes S using the codec registered for encoding. encoding defaults
to the default encoding. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeDecodeError. Other possible values are 'ignore' and 'replace'
as well as any other name registered with codecs.register_error that is
able to handle UnicodeDecodeErrors.
"""
return object() def encode(self, encoding=None, errors=None):
""" 编码,针对unicode """
"""
S.encode([encoding[,errors]]) -> object Encodes S using the codec registered for encoding. encoding defaults
to the default encoding. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that is able to handle UnicodeEncodeErrors.
"""
return object() def endswith(self, suffix, start=None, end=None):
""" 是否以 xxx 结束 """
"""
S.endswith(suffix[, start[, end]]) -> bool Return True if S ends with the specified suffix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
suffix can also be a tuple of strings to try.
"""
return False def expandtabs(self, tabsize=None):
""" 将tab转换成空格,默认一个tab转换成8个空格 """
"""
S.expandtabs([tabsize]) -> string Return a copy of S where all tab characters are expanded using spaces.
If tabsize is not given, a tab size of 8 characters is assumed.
"""
return "" def find(self, sub, start=None, end=None):
""" 寻找子序列位置,如果没找到,返回 -1 """
"""
S.find(sub [,start [,end]]) -> int Return the lowest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation. Return -1 on failure.
"""
return 0 def format(*args, **kwargs): # known special case of str.format
""" 字符串格式化,动态参数,将函数式编程时细说 """
"""
S.format(*args, **kwargs) -> string Return a formatted version of S, using substitutions from args and kwargs.
The substitutions are identified by braces ('{' and '}').
"""
pass def index(self, sub, start=None, end=None):
""" 子序列位置,如果没找到,报错 """
S.index(sub [,start [,end]]) -> int Like S.find() but raise ValueError when the substring is not found.
"""
return 0 def isalnum(self):
""" 是否是字母和数字 """
"""
S.isalnum() -> bool Return True if all characters in S are alphanumeric
and there is at least one character in S, False otherwise.
"""
return False def isalpha(self):
""" 是否是字母 """
"""
S.isalpha() -> bool Return True if all characters in S are alphabetic
and there is at least one character in S, False otherwise.
"""
return False def isdigit(self):
""" 是否是数字 """
"""
S.isdigit() -> bool Return True if all characters in S are digits
and there is at least one character in S, False otherwise.
"""
return False def islower(self):
""" 是否小写 """
"""
S.islower() -> bool Return True if all cased characters in S are lowercase and there is
at least one cased character in S, False otherwise.
"""
return False def isspace(self):
"""
S.isspace() -> bool Return True if all characters in S are whitespace
and there is at least one character in S, False otherwise.
"""
return False def istitle(self):
"""
S.istitle() -> bool Return True if S is a titlecased string and there is at least one
character in S, i.e. uppercase characters may only follow uncased
characters and lowercase characters only cased ones. Return False
otherwise.
"""
return False def isupper(self):
"""
S.isupper() -> bool Return True if all cased characters in S are uppercase and there is
at least one cased character in S, False otherwise.
"""
return False def join(self, iterable):
""" 连接 """
"""
S.join(iterable) -> string Return a string which is the concatenation of the strings in the
iterable. The separator between elements is S.
"""
return "" def ljust(self, width, fillchar=None):
""" 内容左对齐,右侧填充 """
"""
S.ljust(width[, fillchar]) -> string Return S left-justified in a string of length width. Padding is
done using the specified fill character (default is a space).
"""
return "" def lower(self):
""" 变小写 """
"""
S.lower() -> string Return a copy of the string S converted to lowercase.
"""
return "" def lstrip(self, chars=None):
""" 移除左侧空白 """
"""
S.lstrip([chars]) -> string or unicode Return a copy of the string S with leading whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def partition(self, sep):
""" 分割,前,中,后三部分 """
"""
S.partition(sep) -> (head, sep, tail) Search for the separator sep in S, and return the part before it,
the separator itself, and the part after it. If the separator is not
found, return S and two empty strings.
"""
pass def replace(self, old, new, count=None):
""" 替换 """
"""
S.replace(old, new[, count]) -> string Return a copy of string S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
"""
return "" def rfind(self, sub, start=None, end=None):
"""
S.rfind(sub [,start [,end]]) -> int Return the highest index in S where substring sub is found,
such that sub is contained within S[start:end]. Optional
arguments start and end are interpreted as in slice notation. Return -1 on failure.
"""
return 0 def rindex(self, sub, start=None, end=None):
"""
S.rindex(sub [,start [,end]]) -> int Like S.rfind() but raise ValueError when the substring is not found.
"""
return 0 def rjust(self, width, fillchar=None):
"""
S.rjust(width[, fillchar]) -> string Return S right-justified in a string of length width. Padding is
done using the specified fill character (default is a space)
"""
return "" def rpartition(self, sep):
"""
S.rpartition(sep) -> (head, sep, tail) Search for the separator sep in S, starting at the end of S, and return
the part before it, the separator itself, and the part after it. If the
separator is not found, return two empty strings and S.
"""
pass def rsplit(self, sep=None, maxsplit=None):
"""
S.rsplit([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the
delimiter string, starting at the end of the string and working
to the front. If maxsplit is given, at most maxsplit splits are
done. If sep is not specified or is None, any whitespace string
is a separator.
"""
return [] def rstrip(self, chars=None):
"""
S.rstrip([chars]) -> string or unicode Return a copy of the string S with trailing whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def split(self, sep=None, maxsplit=None):
""" 分割, maxsplit最多分割几次 """
"""
S.split([sep [,maxsplit]]) -> list of strings Return a list of the words in the string S, using sep as the
delimiter string. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are removed
from the result.
"""
return [] def splitlines(self, keepends=False):
""" 根据换行分割 """
"""
S.splitlines(keepends=False) -> list of strings Return a list of the lines in S, breaking at line boundaries.
Line breaks are not included in the resulting list unless keepends
is given and true.
"""
return [] def startswith(self, prefix, start=None, end=None):
""" 是否起始 """
"""
S.startswith(prefix[, start[, end]]) -> bool Return True if S starts with the specified prefix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
prefix can also be a tuple of strings to try.
"""
return False def strip(self, chars=None):
""" 移除两段空白 """
"""
S.strip([chars]) -> string or unicode Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
If chars is unicode, S will be converted to unicode before stripping
"""
return "" def swapcase(self):
""" 大写变小写,小写变大写 """
"""
S.swapcase() -> string Return a copy of the string S with uppercase characters
converted to lowercase and vice versa.
"""
return "" def title(self):
"""
S.title() -> string Return a titlecased version of S, i.e. words start with uppercase
characters, all remaining cased characters have lowercase.
"""
return "" def translate(self, table, deletechars=None):
"""
转换,需要先做一个对应表,最后一个表示删除字符集合
intab = "aeiou"
outtab = ""
trantab = maketrans(intab, outtab)
str = "this is string example....wow!!!"
print str.translate(trantab, 'xm')
""" """
S.translate(table [,deletechars]) -> string Return a copy of the string S, where all characters occurring
in the optional argument deletechars are removed, and the
remaining characters have been mapped through the given
translation table, which must be a string of length 256 or None.
If the table argument is None, no translation is applied and
the operation simply removes the characters in deletechars.
"""
return "" def upper(self):
"""
S.upper() -> string Return a copy of the string S converted to uppercase.
"""
return "" def zfill(self, width):
"""方法返回指定长度的字符串,原字符串右对齐,前面填充0。"""
"""
S.zfill(width) -> string Pad a numeric string S with zeros on the left, to fill a field
of the specified width. The string S is never truncated.
"""
return "" def _formatter_field_name_split(self, *args, **kwargs): # real signature unknown
pass def _formatter_parser(self, *args, **kwargs): # real signature unknown
pass def __add__(self, y):
""" x.__add__(y) <==> x+y """
pass def __contains__(self, y):
""" x.__contains__(y) <==> y in x """
pass def __eq__(self, y):
""" x.__eq__(y) <==> x==y """
pass def __format__(self, format_spec):
"""
S.__format__(format_spec) -> string Return a formatted version of S as described by format_spec.
"""
return "" def __getattribute__(self, name):
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y):
""" x.__getitem__(y) <==> x[y] """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass def __getslice__(self, i, j):
"""
x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported.
"""
pass def __ge__(self, y):
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y):
""" x.__gt__(y) <==> x>y """
pass def __hash__(self):
""" x.__hash__() <==> hash(x) """
pass def __init__(self, string=''): # known special case of str.__init__
"""
str(object='') -> string Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
# (copied from class doc)
"""
pass def __len__(self):
""" x.__len__() <==> len(x) """
pass def __le__(self, y):
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y):
""" x.__lt__(y) <==> x<y """
pass def __mod__(self, y):
""" x.__mod__(y) <==> x%y """
pass def __mul__(self, n):
""" x.__mul__(n) <==> x*n """
pass @staticmethod # known case of __new__
def __new__(S, *more):
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y):
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self):
""" x.__repr__() <==> repr(x) """
pass def __rmod__(self, y):
""" x.__rmod__(y) <==> y%x """
pass def __rmul__(self, n):
""" x.__rmul__(n) <==> n*x """
pass def __sizeof__(self):
""" S.__sizeof__() -> size of S in memory, in bytes """
pass def __str__(self):
""" x.__str__() <==> str(x) """
pass str str

str

在最新的Python3版本中,字符串是用Unicode表示的,对于单个字符我们可以用Python提供的ord()函数或字符的整数编码(编码的十进制),用chr()吧编码转换为对应的字符

>>> ord('a')
97
>>> ord('王')
29579
>>> chr(29579)
'王'

注:编码;字符串的乘法;字符串和格式化

1.center居中对齐

 1 def center(self, width, fillchar=None): # real signature unknown; restored from __doc__
2 """
3 S.center(width[, fillchar]) -> str
4 返回新的字符串对象,居中对齐
5 width:宽度,返回的字符串长度
6 fillchar:填充字符
7 Return S centered in a string of length width. Padding is
8 done using the specified fill character (default is a space)
9 """
10 return ""

center

>>> str.center(25,'*')
'********Hello man********'

2.count显示字符出现的次数

 def count(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.count(sub[, start[, end]]) -> int
# 返回整形,子串出现的次数
sub:查询的子串
start:开始索引
end:结束索引 Return the number of non-overlapping occurrences of substring sub in
string S[start:end]. Optional arguments start and end are
interpreted as in slice notation.
"""
return 0

count

>>> str.count("l")
2
>>> str.count("l",3)
1
>>> str.count("l",5,7)
0

3.encode(返回指定编码的字节流)

 def encode(self, encoding='utf-8', errors='strict'): # real signature unknown; restored from __doc__
"""
S.encode(encoding='utf-8', errors='strict') -> bytes
返回指定编码的字节流(老师说是uncode编码) Encode S using the codec registered for encoding. Default encoding
is 'utf-8'. errors may be given to set a different error
handling scheme. Default is 'strict' meaning that encoding errors raise
a UnicodeEncodeError. Other possible values are 'ignore', 'replace' and
'xmlcharrefreplace' as well as any other name registered with
codecs.register_error that can handle UnicodeEncodeErrors.
"""
return b""

encode

>>> 'ABC'.encode('ascii')
b'ABC'
>>> 'ABC'.encode('utf-8')
b'ABC'
>>> '王健'.encode('ascii')
Traceback (most recent call last):
File "<input>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-1: ordinal not in range(128)
>>> '王健'.encode('utf-8')
b'\xe7\x8e\x8b\xe5\x81\xa5'

4.startwith,endwith(判断字符开头及结尾)

 def startswith(self, prefix, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.startswith(prefix[, start[, end]]) -> bool Return True if S starts with the specified prefix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
prefix can also be a tuple of strings to try.
"""
return False def endswith(self, suffix, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.endswith(suffix[, start[, end]]) -> bool Return True if S ends with the specified suffix, False otherwise.
With optional start, test S beginning at that position.
With optional end, stop comparing S at that position.
suffix can also be a tuple of strings to try.
"""
return False

startswith endswith

>>> str.startswith('Hello')

True

>>> str.endswith('an')
True

5.expandtabs(设定制表符的宽度)

 def expandtabs(self, tabsize=8): # real signature unknown; restored from __doc__
"""
S.expandtabs(tabsize=8) -> str
返回新的字符串对象,设定制表符的宽度
Return a copy of S where all tab characters are expanded using spaces.
If tabsize is not given, a tab size of 8 characters is assumed.
"""
return ""

expand tabs

>>> str = 'hello\tJason'
>>> str
'hello\tJason'
>>> print(str)
hello Jason
>>> print(str.expandtabs())
hello Jason
>>> print(str.expandtabs(8))
hello Jason
>>> print(str.expandtabs(16))
hello Jason

6.find(查找子串)

 >>> str = 'hello\tJason'
>>> str
'hello\tJason'
>>> print(str)
hello Jason
>>> print(str.expandtabs())
hello Jason
>>> print(str.expandtabs(8))
hello Jason
>>> print(str.expandtabs(16))
hello Jason

find

>>> str.find('h')
0
>>> str.find('x')
-1

7.format(格式化输出)

 def format(*args, **kwargs): # known special case of str.format
"""
S.format(*args, **kwargs) -> str
格式化字符串,返回新的字符串对象,类似占位符 Return a formatted version of S, using substitutions from args and kwargs.
The substitutions are identified by braces ('{' and '}').
"""
pass

format

>>> str = "hello {0}"
>>> str.format('Jason')
'hello Jason'
>>> str = "hello {0}{1}"
>>> str.format('Jason','!')
'hello Jason!'
>>> str = "hello {name}"
>>> str.format(name='Jason')
'hello Jason'

8.format_map(格式化输出)

def format_map(self, mapping): # real signature unknown; restored from __doc__
"""
S.format_map(mapping) -> str
格式化字符串,返回新的字符串对象
mapping:字典对象,用来替换站位符
Return a formatted version of S, using substitutions from mapping.
The substitutions are identified by braces ('{' and '}').
"""
return ""

format_map

>>> str = "hello {name}"

>>> str.format_map({"name":"Jack"})
'hello Jack'

9.index(查找子串,返回子串的索引)

 def index(self, sub, start=None, end=None): # real signature unknown; restored from __doc__
"""
S.index(sub[, start[, end]]) -> int
查找子串,使用方法同find,不同是如果不存在会报错
Like S.find() but raise ValueError when the substring is not found.
"""
return 0

index

>>> str = 'Hello James'
>>> str.index('Hello')
0
>>> str.index('o')
4
>>> str.index('k')
Traceback (most recent call last):
File "<input>", line 1, in <module>
ValueError: substring not found

10.isdigit(判断是否由数字组成,同上)

def isdigit(self): # real signature unknown; restored from __doc__
"""
S.isdigit() -> bool
判断是否由数字组成
Return True if all characters in S are digits
and there is at least one character in S, False otherwise.
"""
return False

isdigit

>>> str = '1234'
>>> str.isdigit()
True
>>> str = '1234.22'
>>> str.isdigit()
False

11.join(拼接序列)

 def join(self, iterable): # real signature unknown; restored from __doc__
"""
S.join(iterable) -> str
以当前字符串为分隔符,拼接序列对象(如列表、元祖等),返回新的字符串对象
iterable:要拼接的序列化对象
Return a string which is the concatenation of the strings in the
iterable. The separator between elements is S.
"""
return ""

join

>>> li = ['hi','Jason']
>>> '*'.join(li)
'hi*Jason'

12.ljust(左对齐)

 def ljust(self, width, fillchar=None): # real signature unknown; restored from __doc__
"""
S.ljust(width[, fillchar]) -> str
左对齐,返回新的字符串对象
width:新出的字符串对象宽度
fillchar:填充字符串,默认是空格
Return S left-justified in a Unicode string of length width. Padding is
done using the specified fill character (default is a space).
"""
return ""

ljust

>>> str = 'Jason'
>>> str.ljust(16,'*')
'Jason***********'

13.strip,lstrip(左),rstrip(右)(脱去的空格或自定子串)

 def strip(self, chars=None): # real signature unknown; restored from __doc__
"""
S.strip([chars]) -> str Return a copy of the string S with leading and trailing
whitespace removed.
If chars is given and not None, remove characters in chars instead.
"""
return ""
def lstrip(self, chars=None): # real signature unknown; restored from __doc__
"""
S.lstrip([chars]) -> str
脱去左侧的空格或自定子串
chars:要脱去的子串
Return a copy of the string S with leading whitespace removed.
If chars is given and not None, remove characters in chars instead.
"""
return ""

strip

>>> str = ' Jason'
>>> str.strip()
'Jason'
>>> str = ' Jason'
>>> str.lstrip()
'Jason'
>>> str.rstrip()
' Jason'

14.maketrans和translate

def maketrans(self, *args, **kwargs): # real signature unknown
"""
Return a translation table usable for str.translate().
创建translate对照表
If there is only one argument, it must be a dictionary mapping Unicode
ordinals (integers) or characters to Unicode ordinals, strings or None.
Character keys will be then converted to ordinals.
If there are two arguments, they must be strings of equal length, and
in the resulting dictionary, each character in x will be mapped to the
character at the same position in y. If there is a third argument, it
must be a string, whose characters will be mapped to None in the result.
"""
pass def translate(self, table): # real signature unknown; restored from __doc__
"""
S.translate(table) -> str
通过对照表完成字符替换
table:对照表对象,maketrans返回的对象
Return a copy of the string S in which each character has been mapped
through the given translation table. The table must implement
lookup/indexing via __getitem__, for instance a dictionary or list,
mapping Unicode ordinals to Unicode ordinals, strings, or None. If
this operation raises LookupError, the character is left untouched.
Characters mapped to None are deleted.
"""
return ""

maketrans和translate

>>> tranli =str.maketrans('23','yt')
>>> s = '123445'
>>> s.translate(tranli)
'1yt445

15.partition(返回分隔符分隔的元祖,从左侧开始查找)

 def partition(self, sep): # real signature unknown; restored from __doc__
"""
S.partition(sep) -> (head, sep, tail)
返回一个三个元素的元祖,第一个元素为分隔符左侧的子串,第二个元素为分隔符,第三个元素为分隔符右侧的子串
sep:分隔符 Search for the separator sep in S, and return the part before it,
the separator itself, and the part after it. If the separator is not
found, return S and two empty strings.
"""
pass

partition

>>> str = "https://jsdd.com.cn"
>>> str.partition("//")
('https:', '//', 'jsdd.com.cn')

16.replace(子串替换)

 def replace(self, old, new, count=None): # real signature unknown; restored from __doc__
"""
S.replace(old, new[, count]) -> str
子串替换
old:旧的子串
new:新的子串
count:替换的次数
Return a copy of S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
"""
return ""

replace

>>> str = "1234561231"
>>> str.replace("1","a")
'a23456a23a'
>>> str.replace("1","a",1)
'a234561231'

17.split(分隔字符串,从左侧开始), splitlines(以换行符为分隔符分隔字符串)

 def split(self, sep=None, maxsplit=-1): # real signature unknown; restored from __doc__
"""
S.split(sep=None, maxsplit=-1) -> list of strings
分隔字符串
sep:分隔符
maxsplit:最多分隔的次数
Return a list of the words in S, using sep as the
delimiter string. If maxsplit is given, at most maxsplit
splits are done. If sep is not specified or is None, any
whitespace string is a separator and empty strings are
removed from the result.
"""
return []

split

 def splitlines(self, keepends=None): # real signature unknown; restored from __doc__
"""
S.splitlines([keepends]) -> list of strings
以换行符为分隔符分隔字符串
keepends:是否保留换行符
Return a list of the lines in S, breaking at line boundaries.
Line breaks are not included in the resulting list unless keepends
is given and true.
"""
return []

splitlines

>>> str = "Jason"
>>> str.split()
['Jason']
>>> str.split('a')
['J', 'son']

>>> str = "Jason\nHaHa\nJack\n"
>>> str.splitlines()
['Jason', 'HaHa', 'Jack']

18.zfill(右对齐,以字符0填充)

 def zfill(self, width): # real signature unknown; restored from __doc__
"""
S.zfill(width) -> str
右对齐,以字符0填充
width:宽度
Pad a numeric string S with zeros on the left, to fill a field
of the specified width. The string S is never truncated.
"""
return ""

zfill

>>> str = 'Python'
>>> str.zfill(10)
'0000Python'

五、列表

Python的列表是一种内置的数据类型,是由Python的基本数据类型组成的有序的集合。有点类似C语言的数组,但与数组不同的是,Python在定义列表的时候不用指定列表的容积(长度),可根据需要任意扩展,另外列表的内的元素可以是不同的数据类型,当然既然是任何数据类型,当然也包括另一个列表也就是嵌套。Python中列表使用中括号[]括起来,例如['Jack', 22, 'James', False, ['Jack', 22, 'James', False]].

1、列表的切片

通字符串一样列表也支持切片操作,例如我们有一个列表A_list = ['Michael', 'Bob', 'Tracy']

>>> A_list = ['Jack',22,'James',False]
>>> B_list = ['Jack',22,'James',False,A_list]
>>> print(B_list)
['Jack', 22, 'James', False, ['Jack', 22, 'James', False]]

如:[11,22,33]、['Jason', 'James']

每个列表都具备如下功能:

class list(object):
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
"""
def append(self, p_object): # real signature unknown; restored from __doc__
""" L.append(object) -- append object to end """
pass def count(self, value): # real signature unknown; restored from __doc__
""" L.count(value) -> integer -- return number of occurrences of value """
return 0 def extend(self, iterable): # real signature unknown; restored from __doc__
""" L.extend(iterable) -- extend list by appending elements from the iterable """
pass def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
L.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0 def insert(self, index, p_object): # real signature unknown; restored from __doc__
""" L.insert(index, object) -- insert object before index """
pass def pop(self, index=None): # real signature unknown; restored from __doc__
"""
L.pop([index]) -> item -- remove and return item at index (default last).
Raises IndexError if list is empty or index is out of range.
"""
pass def remove(self, value): # real signature unknown; restored from __doc__
"""
L.remove(value) -- remove first occurrence of value.
Raises ValueError if the value is not present.
"""
pass def reverse(self): # real signature unknown; restored from __doc__
""" L.reverse() -- reverse *IN PLACE* """
pass def sort(self, cmp=None, key=None, reverse=False): # real signature unknown; restored from __doc__
"""
L.sort(cmp=None, key=None, reverse=False) -- stable sort *IN PLACE*;
cmp(x, y) -> -1, 0, 1
"""
pass def __add__(self, y): # real signature unknown; restored from __doc__
""" x.__add__(y) <==> x+y """
pass def __contains__(self, y): # real signature unknown; restored from __doc__
""" x.__contains__(y) <==> y in x """
pass def __delitem__(self, y): # real signature unknown; restored from __doc__
""" x.__delitem__(y) <==> del x[y] """
pass def __delslice__(self, i, j): # real signature unknown; restored from __doc__
"""
x.__delslice__(i, j) <==> del x[i:j] Use of negative indices is not supported.
"""
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__
"""
x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported.
"""
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __iadd__(self, y): # real signature unknown; restored from __doc__
""" x.__iadd__(y) <==> x+=y """
pass def __imul__(self, y): # real signature unknown; restored from __doc__
""" x.__imul__(y) <==> x*=y """
pass def __init__(self, seq=()): # known special case of list.__init__
"""
list() -> new empty list
list(iterable) -> new list initialized from iterable's items
# (copied from class doc)
"""
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass def __mul__(self, n): # real signature unknown; restored from __doc__
""" x.__mul__(n) <==> x*n """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __reversed__(self): # real signature unknown; restored from __doc__
""" L.__reversed__() -- return a reverse iterator over the list """
pass def __rmul__(self, n): # real signature unknown; restored from __doc__
""" x.__rmul__(n) <==> n*x """
pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__
""" x.__setitem__(i, y) <==> x[i]=y """
pass def __setslice__(self, i, j, y): # real signature unknown; restored from __doc__
"""
x.__setslice__(i, j, y) <==> x[i:j]=y Use of negative indices is not supported.
"""
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" L.__sizeof__() -- size of L in memory, in bytes """
pass __hash__ = None list

list

1)列表中索引号为n的元素(一样是从0开始计数哦)

>>> A_list[1]
22

2)从第m个元素到第n个元素

>>> A_list[0:2]
['Jack', 22]

3)从第m个元素到第n个元素,步长为p(也就是每隔p-1个字符)

>>> A_list[0:3:2]
['Jack', 'James']

说明:同字符串一样,列表的切片同样省略索引号和支持复数,用法与字符串一样,这里就不复述了。

2、列表的内置方法

Python中查看一个对象的内置方法和属性可以使用内置的dir方法,比如我们查看列表A_list的方法和属性

>>> dir(A_list)
['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 'remove', 'reverse', 'sort']

>>> A_list = ['Jack',22,'James',False]

>>> A_list.append('Jason')# 在末尾插入一个新的元素

>>> A_list
['Jack', 22, 'James', False, 'Jason']
>>> A_list.index(1,'Michael')# 在指定位置(索引号)插入一个新的元素

>>> A_list
['Jack', 'Michael', 22, 'James', False, 'Jason']
>>> A_list.pop()#删除最后一个元素,并返回该元素,如果列表已经为空在执行pop方法会报错,类似IndexError: pop from empty list

'Jason'
>>> A_list
['Jack', 'Michael', 22, 'James', False]
>>> A_list.remove('Jack')# 删除指定的元素,注意这里接受的参数是元素,而不是索引号,如果元素不存在则报错,类似ValueError:

>>> A_list
['Michael', 22, 'James', False]
>>> A_list.remove('Jack')
Traceback (most recent call last):
File "<input>", line 1, in <module>
ValueError: list.remove(x): x not in list
>>> A_list.index('James')# 返回指定元素所在位置的索引号,如果元素不存在则报错ValueError: 'dafda' is not in list

2
>>> A_list.sort()
Traceback (most recent call last):
File "<input>", line 1, in <module>
TypeError: unorderable types: int() < str()
>>> A_list
['Michael', 22, 'James', False]
>>> A_list.remove(22)
>>> A_list
['Michael', 'James', False]
>>> A_list.sort()
Traceback (most recent call last):
File "<input>", line 1, in <module>
TypeError: unorderable types: bool() < str()
>>> A_list.remove(False)
>>> A_list.sort()#排序,注意Python3已经不支持不同类型数据的排序,如果列表内元素的类型不一致,就会报错,类似TypeError: unorderable types: str() < list()

>>> A_list
['James', 'Michael']
>>> A_list.reverse()# 翻转列表的元素位置

>>> A_list
['Michael', 'James']
>>> A_list.extend(B_list)# 将另一个列表的每一个元素追加到列表的末尾,注意与append不同,append会把另一列表当成一个元素追加到列表的末尾

>>> A_list
['Michael', 'James', 'Jack', 22, 'James', False, [...]]
>>> A_list.count('James')# 返回列表的某一个元素重复的个数,如果元素不存在返回0,不会报错

2

我们上面说index方法和remove方法只能返回或删除第一查找到的元素,如果一个列表中重复出现多次我们如何处理呢,这时候我们可以这么处理

全部删除:原理就是先求出出现了多少次,然后通过循环删除

 #!/usr/bin/env python
# coding:utf-8
name_list = ['Michael', 'Jack', 'Bob', 'Tracy', 'Peter', 'Jack'] # 这里有两'Jack'
# 返回所有'Jack'的索引
for i in range(name_list.count('Jack')):
name_list.remove('Jack')
print(name_list)

uniq_item

查询所有的索引号,原理就是先求出一共出现了多少次,第一次直接查找返回说因,从第二次开始开始,从上一次的索引位置的下一个位置进行切片,然后再进行查,那么这一次的索引号就是上一次的索引号+加上本次的索引+1,依次类推

 #!/usr/bin/env python
# coding:utf-8
name_list = ['Jack', 'Michael', 'Jack', 'Bob', 'Tracy', 'Peter', 'Jack'] # 这里有三个'Jack'
# 返回所有'Jack'的索引
index_num = 0 # 定义初始索引号
index_list = [] # 定义用来存储索引号的列表
for i in range(name_list.count('Jack')):
if i != 0: # i不等于0也就是说不是第一次查找
index_num = name_list[index_num+1:].index('Jack') + index_num + 1
else: # 否则就是第一次查找,直接返回索引号即可
index_num = name_list.index('Jack')
index_list.append(index_num) # 将索引号追加到index_list中
print(index_list)

uniq_index_item

注:排序;

六、元组

如:(11,22,33)、('Jason', 'James')

每个元组都具备如下功能:

class tuple(object):
"""
tuple() -> empty tuple
tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object.
"""
def count(self, value): # real signature unknown; restored from __doc__
""" T.count(value) -> integer -- return number of occurrences of value """
return 0 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__
"""
T.index(value, [start, [stop]]) -> integer -- return first index of value.
Raises ValueError if the value is not present.
"""
return 0 def __add__(self, y): # real signature unknown; restored from __doc__
""" x.__add__(y) <==> x+y """
pass def __contains__(self, y): # real signature unknown; restored from __doc__
""" x.__contains__(y) <==> y in x """
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass def __getnewargs__(self, *args, **kwargs): # real signature unknown
pass def __getslice__(self, i, j): # real signature unknown; restored from __doc__
"""
x.__getslice__(i, j) <==> x[i:j] Use of negative indices is not supported.
"""
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __hash__(self): # real signature unknown; restored from __doc__
""" x.__hash__() <==> hash(x) """
pass def __init__(self, seq=()): # known special case of tuple.__init__
"""
tuple() -> empty tuple
tuple(iterable) -> tuple initialized from iterable's items If the argument is a tuple, the return value is the same object.
# (copied from class doc)
"""
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass def __mul__(self, n): # real signature unknown; restored from __doc__
""" x.__mul__(n) <==> x*n """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __rmul__(self, n): # real signature unknown; restored from __doc__
""" x.__rmul__(n) <==> n*x """
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" T.__sizeof__() -- size of T in memory, in bytes """
pass tuple

tuple

元祖和列表非常类似,但是元祖一旦初始化就不能修改,所以元祖除了可以切片外没有列表的那些方法。

但是我们所说的元祖的不可变不是绝对的,也可以是“可变的”,那就是元祖里的元素是其他可变的数据类型,如列表等

例如:t = ('a', 'b', ['A', 'B'])

注意里面列表,我们要对这个列表进行一些修改操作:

>>> t = ('a', 'b', ['A', 'B'])
>>> t[2][0] = 'X'
>>> t
('a', 'b', ['X', 'B'])
>>> t[2].append('C')
>>> t
('a', 'b', ['X', 'B', 'C'])

可以看出如果元祖里有可变数据类型的元素,那么该元素是依然可以修改的,这使得元祖貌似被修改了,其实并没有修改,因为Python一切皆指针。

七、字典

一、字典简介

字典dict(dictionary),在其他语言中也成为map,使用键-值(key-value)的形式存储和展现,具有极快的查找速度。

字典的定义

d = {'key':value,...}

字典可以嵌套,value也可以使用列表等数据类型

字典通过键获取键所对应的值

d[key]

如:{'name': 'Jason', 'age': 18} 、{'host': '2.2.2.2', 'port': 80]}

1、clear(清除字典所有元素)

代码:

1 def clear(self): # real signature unknown; restored from __doc__
2 """ D.clear() -> None. Remove all items from D.
3 清除所有元素
4 """
5 pass

示例:

>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.clear()
>>> dic
{}

2、copy(浅拷贝)

代码:

1 def copy(self): # real signature unknown; restored from __doc__
2 """ D.copy() -> a shallow copy of D
3 浅拷贝,返回的是一个新的字典对象
4 """
5 pass

示例:

>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic2 = dic.copy()
>>> dic2
{'age': 25, 'name': 'Jason', 'address': 'beijing china'}

注意:拷贝和赋值dic2 = dic完全不一样,等到讲到深浅拷贝的时候再来探讨这个问题

3、fromkeys(创建新的字典对象)

代码:

1 @staticmethod # known case
2 def fromkeys(*args, **kwargs): # real signature unknown
3 """ Returns a new dict with keys from iterable and values equal to value.
4 用于创建一个新字典,以序列seq中元素做字典的键,value为字典所有键对应的初始值
5 """
6 pass

示例:

>>> dic = dict.fromkeys(['name','age'],10)
>>> dic
{'age': 10, 'name': 10}

4、get(获取键所对应的值)

代码:

1 def get(self, k, d=None): # real signature unknown; restored from __doc__
2 """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.
3 获取键所对应的值如果存在返回值,如果不存在返回d所定义的值
4 k:key
5 d:默认值,如果不存在返回的值
6 """
7 pass

示例:

>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.get('name')
'Jason'
>>> dic.get('hobby','23')
'23'
>>> dic.get('hobby')

注意:与d[key]取值不同的是,get方法如果key不存在则返回默认值,如果没定义返回的是None,而d[key]这种方式key不存在则会报错

>>> dic['hobby']
Traceback (most recent call last):
File "<input>", line 1, in <module>
KeyError: 'hobby'

5、items(返回键值组成的元祖)

代码:

1 def items(self): # real signature unknown; restored from __doc__
2 """ D.items() -> a set-like object providing a view on D's items
3 返回键值组成的元祖列表,也就是同时返回键和值
4 """
5 pass

示例:

>>> dic.items()
dict_items([('age', 25), ('name', 'Jason'), ('address', 'beijing china')])

6、keys(返回字典的key)

代码:

1 def keys(self): # real signature unknown; restored from __doc__
2 """ D.keys() -> a set-like object providing a view on D's keys
3 返回字典的所有的key
4 """
5 pass

示例:

>>> dic.keys()
dict_keys(['age', 'name', 'address'])

说明:2.X返回的直接是列表对象,3.X返回的dict_keys对象,但是也能通过in做是否存在的判断或循环

7、pop(删除指定key的元素,并返回key所对应的值)

代码:

1 def pop(self, k, d=None): # real signature unknown; restored from __doc__
2 """
3 D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
4 If key is not found, d is returned if given, otherwise KeyError is raised
5 删除指定key的元素,并返回key所对应的值,如果不存在返回默认值
6 k:key
7 d:默认值,如果不存在返回的值
8 """
9 pass

示例:

>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china'}
>>> dic.pop('name')
'Jason'
>>> dic
{'age': 25, 'address': 'beijing china'}
>>> dic.pop('hobby','123')
'123'

8、popitem(删除元素)

代码

1 def popitem(self): # real signature unknown; restored from __doc__
2 """
3 D.popitem() -> (k, v), remove and return some (key, value) pair as a
4 2-tuple; but raise KeyError if D is empty.
5 删除元素并返回删除的元素key和value组成的元祖
6 """
7 pass

示例:

>>> dic = {'name':'zhangxiaoyu', 'age':35, 'address':'beijing china'}
>>> dic.popitem()
('age', 35)
>>> dic
{'address': 'beijing china', 'name': 'zhangxiaoyu'}

注意:由于字典是无序的,所以使用这个方法删除的不一定是哪个元素,所以慎用

9、setdefault(设置默认值,这个方法要与get方法配合使用相当于get方法的d参数)

代码:

1 def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
2 """ D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D
3 设置默认值,这个方法要与get方法配合使用相当于get方法的d参数,同样也适用于d[key]这种取值方法
4
5 """
6 pass

示例:

>>> dic = {'name':'Jason', 'age':25, 'address':'beijing china'}
>>> dic.setdefault('hobby',"basketball")
'basketball'
>>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china', 'hobby': 'basketball'}

感觉完全是设置了一个新的键值对

10、update(将另一个字典的键值添加到当前字典中)

代码:

 1 def update(self, E=None, **F): # known special case of dict.update
2 """
3 D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
4 If E is present and has a .keys() method, then does: for k in E: D[k] = E[k]
5 If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v
6 In either case, this is followed by: for k in F: D[k] = F[k]
7 将另一个字典的键值添加到当前字典中
8 不存在的键直接添加,存在的键将被覆盖
9 """
10 pass

示例:

>> dic
{'age': 25, 'name': 'Jason', 'address': 'beijing china', 'hobby': 'basketball'}
>>> dic2 = {'gender':'male','name':'luis'}
>>> dic.update(dic2)
>>> dic
{'age': 25, 'address': 'beijing china', 'gender': 'male', 'hobby': 'basketball', 'name': 'luis'}

11、values(返回所有的值)

代码:

1 def values(self): # real signature unknown; restored from __doc__
2 """ D.values() -> an object providing a view on D's values
3 返回字典所有的值
4 """
5 pass

示例:

>>> dic.values()
dict_values([25, 'beijing china', 'male', 'basketball', 'luis'])

ps:循环时,默认循环key

每个字典都具备如下功能:

 class dict(object):
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
""" def clear(self): # real signature unknown; restored from __doc__
""" 清除内容 """
""" D.clear() -> None. Remove all items from D. """
pass def copy(self): # real signature unknown; restored from __doc__
""" 浅拷贝 """
""" D.copy() -> a shallow copy of D """
pass @staticmethod # known case
def fromkeys(S, v=None): # real signature unknown; restored from __doc__
"""
dict.fromkeys(S[,v]) -> New dict with keys from S and values equal to v.
v defaults to None.
"""
pass def get(self, k, d=None): # real signature unknown; restored from __doc__
""" 根据key获取值,d是默认值 """
""" D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """
pass def has_key(self, k): # real signature unknown; restored from __doc__
""" 是否有key """
""" D.has_key(k) -> True if D has a key k, else False """
return False def items(self): # real signature unknown; restored from __doc__
""" 所有项的列表形式 """
""" D.items() -> list of D's (key, value) pairs, as 2-tuples """
return [] def iteritems(self): # real signature unknown; restored from __doc__
""" 项可迭代 """
""" D.iteritems() -> an iterator over the (key, value) items of D """
pass def iterkeys(self): # real signature unknown; restored from __doc__
""" key可迭代 """
""" D.iterkeys() -> an iterator over the keys of D """
pass def itervalues(self): # real signature unknown; restored from __doc__
""" value可迭代 """
""" D.itervalues() -> an iterator over the values of D """
pass def keys(self): # real signature unknown; restored from __doc__
""" 所有的key列表 """
""" D.keys() -> list of D's keys """
return [] def pop(self, k, d=None): # real signature unknown; restored from __doc__
""" 获取并在字典中移除 """
"""
D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
If key is not found, d is returned if given, otherwise KeyError is raised
"""
pass def popitem(self): # real signature unknown; restored from __doc__
""" 获取并在字典中移除 """
"""
D.popitem() -> (k, v), remove and return some (key, value) pair as a
2-tuple; but raise KeyError if D is empty.
"""
pass def setdefault(self, k, d=None): # real signature unknown; restored from __doc__
""" 如果key不存在,则创建,如果存在,则返回已存在的值且不修改 """
""" D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D """
pass def update(self, E=None, **F): # known special case of dict.update
""" 更新
{'name':'alex', 'age': 18000}
[('name','sbsbsb'),]
"""
"""
D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
If E present and has a .keys() method, does: for k in E: D[k] = E[k]
If E present and lacks .keys() method, does: for (k, v) in E: D[k] = v
In either case, this is followed by: for k in F: D[k] = F[k]
"""
pass def values(self): # real signature unknown; restored from __doc__
""" 所有的值 """
""" D.values() -> list of D's values """
return [] def viewitems(self): # real signature unknown; restored from __doc__
""" 所有项,只是将内容保存至view对象中 """
""" D.viewitems() -> a set-like object providing a view on D's items """
pass def viewkeys(self): # real signature unknown; restored from __doc__
""" D.viewkeys() -> a set-like object providing a view on D's keys """
pass def viewvalues(self): # real signature unknown; restored from __doc__
""" D.viewvalues() -> an object providing a view on D's values """
pass def __cmp__(self, y): # real signature unknown; restored from __doc__
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __contains__(self, k): # real signature unknown; restored from __doc__
""" D.__contains__(k) -> True if D has a key k, else False """
return False def __delitem__(self, y): # real signature unknown; restored from __doc__
""" x.__delitem__(y) <==> del x[y] """
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __getitem__(self, y): # real signature unknown; restored from __doc__
""" x.__getitem__(y) <==> x[y] """
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __init__(self, seq=None, **kwargs): # known special case of dict.__init__
"""
dict() -> new empty dictionary
dict(mapping) -> new dictionary initialized from a mapping object's
(key, value) pairs
dict(iterable) -> new dictionary initialized as if via:
d = {}
for k, v in iterable:
d[k] = v
dict(**kwargs) -> new dictionary initialized with the name=value pairs
in the keyword argument list. For example: dict(one=1, two=2)
# (copied from class doc)
"""
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __setitem__(self, i, y): # real signature unknown; restored from __doc__
""" x.__setitem__(i, y) <==> x[i]=y """
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" D.__sizeof__() -> size of D in memory, in bytes """
pass __hash__ = None dict

dict

练习:元素分类
有如下值集合 [11,22,33,44,55,66,77,88,99,90...],将所有大于 66 的值保存至字典的第一个key中,将小于 66 的值保存至第二个key的值中。
即: {'k1': 大于66 , 'k2': 小于66}

八、set集合

set是一个无序且不重复的元素集合

class set(object):
"""
set() -> new empty set object
set(iterable) -> new set object Build an unordered collection of unique elements.
"""
def add(self, *args, **kwargs): # real signature unknown
""" 添加 """
"""
Add an element to a set. This has no effect if the element is already present.
"""
pass def clear(self, *args, **kwargs): # real signature unknown
""" Remove all elements from this set. """
pass def copy(self, *args, **kwargs): # real signature unknown
""" Return a shallow copy of a set. """
pass def difference(self, *args, **kwargs): # real signature unknown
"""
Return the difference of two or more sets as a new set. (i.e. all elements that are in this set but not the others.)
"""
pass def difference_update(self, *args, **kwargs): # real signature unknown
""" 删除当前set中的所有包含在 new set 里的元素 """
""" Remove all elements of another set from this set. """
pass def discard(self, *args, **kwargs): # real signature unknown
""" 移除元素 """
"""
Remove an element from a set if it is a member. If the element is not a member, do nothing.
"""
pass def intersection(self, *args, **kwargs): # real signature unknown
""" 取交集,新创建一个set """
"""
Return the intersection of two or more sets as a new set. (i.e. elements that are common to all of the sets.)
"""
pass def intersection_update(self, *args, **kwargs): # real signature unknown
""" 取交集,修改原来set """
""" Update a set with the intersection of itself and another. """
pass def isdisjoint(self, *args, **kwargs): # real signature unknown
""" 如果没有交集,返回true """
""" Return True if two sets have a null intersection. """
pass def issubset(self, *args, **kwargs): # real signature unknown
""" 是否是子集 """
""" Report whether another set contains this set. """
pass def issuperset(self, *args, **kwargs): # real signature unknown
""" 是否是父集 """
""" Report whether this set contains another set. """
pass def pop(self, *args, **kwargs): # real signature unknown
""" 移除 """
"""
Remove and return an arbitrary set element.
Raises KeyError if the set is empty.
"""
pass def remove(self, *args, **kwargs): # real signature unknown
""" 移除 """
"""
Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError.
"""
pass def symmetric_difference(self, *args, **kwargs): # real signature unknown
""" 差集,创建新对象"""
"""
Return the symmetric difference of two sets as a new set. (i.e. all elements that are in exactly one of the sets.)
"""
pass def symmetric_difference_update(self, *args, **kwargs): # real signature unknown
""" 差集,改变原来 """
""" Update a set with the symmetric difference of itself and another. """
pass def union(self, *args, **kwargs): # real signature unknown
""" 并集 """
"""
Return the union of sets as a new set. (i.e. all elements that are in either set.)
"""
pass def update(self, *args, **kwargs): # real signature unknown
""" 更新 """
""" Update a set with the union of itself and others. """
pass def __and__(self, y): # real signature unknown; restored from __doc__
""" x.__and__(y) <==> x&y """
pass def __cmp__(self, y): # real signature unknown; restored from __doc__
""" x.__cmp__(y) <==> cmp(x,y) """
pass def __contains__(self, y): # real signature unknown; restored from __doc__
""" x.__contains__(y) <==> y in x. """
pass def __eq__(self, y): # real signature unknown; restored from __doc__
""" x.__eq__(y) <==> x==y """
pass def __getattribute__(self, name): # real signature unknown; restored from __doc__
""" x.__getattribute__('name') <==> x.name """
pass def __ge__(self, y): # real signature unknown; restored from __doc__
""" x.__ge__(y) <==> x>=y """
pass def __gt__(self, y): # real signature unknown; restored from __doc__
""" x.__gt__(y) <==> x>y """
pass def __iand__(self, y): # real signature unknown; restored from __doc__
""" x.__iand__(y) <==> x&=y """
pass def __init__(self, seq=()): # known special case of set.__init__
"""
set() -> new empty set object
set(iterable) -> new set object Build an unordered collection of unique elements.
# (copied from class doc)
"""
pass def __ior__(self, y): # real signature unknown; restored from __doc__
""" x.__ior__(y) <==> x|=y """
pass def __isub__(self, y): # real signature unknown; restored from __doc__
""" x.__isub__(y) <==> x-=y """
pass def __iter__(self): # real signature unknown; restored from __doc__
""" x.__iter__() <==> iter(x) """
pass def __ixor__(self, y): # real signature unknown; restored from __doc__
""" x.__ixor__(y) <==> x^=y """
pass def __len__(self): # real signature unknown; restored from __doc__
""" x.__len__() <==> len(x) """
pass def __le__(self, y): # real signature unknown; restored from __doc__
""" x.__le__(y) <==> x<=y """
pass def __lt__(self, y): # real signature unknown; restored from __doc__
""" x.__lt__(y) <==> x<y """
pass @staticmethod # known case of __new__
def __new__(S, *more): # real signature unknown; restored from __doc__
""" T.__new__(S, ...) -> a new object with type S, a subtype of T """
pass def __ne__(self, y): # real signature unknown; restored from __doc__
""" x.__ne__(y) <==> x!=y """
pass def __or__(self, y): # real signature unknown; restored from __doc__
""" x.__or__(y) <==> x|y """
pass def __rand__(self, y): # real signature unknown; restored from __doc__
""" x.__rand__(y) <==> y&x """
pass def __reduce__(self, *args, **kwargs): # real signature unknown
""" Return state information for pickling. """
pass def __repr__(self): # real signature unknown; restored from __doc__
""" x.__repr__() <==> repr(x) """
pass def __ror__(self, y): # real signature unknown; restored from __doc__
""" x.__ror__(y) <==> y|x """
pass def __rsub__(self, y): # real signature unknown; restored from __doc__
""" x.__rsub__(y) <==> y-x """
pass def __rxor__(self, y): # real signature unknown; restored from __doc__
""" x.__rxor__(y) <==> y^x """
pass def __sizeof__(self): # real signature unknown; restored from __doc__
""" S.__sizeof__() -> size of S in memory, in bytes """
pass def __sub__(self, y): # real signature unknown; restored from __doc__
""" x.__sub__(y) <==> x-y """
pass def __xor__(self, y): # real signature unknown; restored from __doc__
""" x.__xor__(y) <==> x^y """
pass __hash__ = None set

set

>>> old_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
}
>>> new_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 },
}
>>> a=set(old_dict)
>>> b=set(new_dict)
>>> a.difference(b)
{'#2'}
>>> a.intersection(b)
{'#1', '#3'}
>>> a.symmetric_difference(b)
{'#4', '#2'}

set exercise

if __name__ == '__main__':
old_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 }
} new_dict = {
"#1":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':'c1', 'cpu_count': 2, 'mem_capicity': 80 },
"#4":{ 'hostname':'c2', 'cpu_count': 2, 'mem_capicity': 80 }
} s1 = set(old_dict)
s2 = set(new_dict) new_list = [] new_set = s1.difference(s2)
for new_item in new_set:
new_list.append(old_dict[new_item]) print(new_list)
print(new_set)
print(s1)

set update conf

##set update conf output

[{'hostname': 'c1', 'mem_capicity': 80, 'cpu_count': 2}]
{'#2'}
{'#3', '#2', '#1'}

练习:寻找差异
# 数据库中原有
old_dict = {
"#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
"#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
} # cmdb 新汇报的数据
new_dict = {
"#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
"#4":{ 'hostname':c2, 'cpu_count': 2, 'mem_capicity': 80 }
} 需要删除:?
需要新建:?
需要更新:? 注意:无需考虑内部元素是否改变,只要原来存在,新汇报也存在,就是需要更新
练习:寻找差异
# 数据库中原有
old_dict = {
"#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 },
"#2":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
"#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
} # cmdb 新汇报的数据
new_dict = {
"#1":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 800 },
"#3":{ 'hostname':c1, 'cpu_count': 2, 'mem_capicity': 80 }
"#4":{ 'hostname':c2, 'cpu_count': 2, 'mem_capicity': 80 }
} 需要删除:?
需要新建:?
需要更新:? 注意:无需考虑内部元素是否改变,只要原来存在,新汇报也存在,就是需要更新

exercise

九.深浅拷贝()

# 浅拷贝
# copy.copy()
# 深拷贝
# copy.deepcopy()
# 赋值
# =
# 数字和字符串的浅拷贝、深拷贝、和赋值都是引用的相同的内存地址
 """Generic (shallow and deep) copying operations.

 Interface summary:

         import copy

         x = copy.copy(y)        # make a shallow copy of y
x = copy.deepcopy(y) # make a deep copy of y For module specific errors, copy.Error is raised. The difference between shallow and deep copying is only relevant for
compound objects (objects that contain other objects, like lists or
class instances). - A shallow copy constructs a new compound object and then (to the
extent possible) inserts *the same objects* into it that the
original contains. - A deep copy constructs a new compound object and then, recursively,
inserts *copies* into it of the objects found in the original. Two problems often exist with deep copy operations that don't exist
with shallow copy operations: a) recursive objects (compound objects that, directly or indirectly,
contain a reference to themselves) may cause a recursive loop b) because deep copy copies *everything* it may copy too much, e.g.
administrative data structures that should be shared even between
copies Python's deep copy operation avoids these problems by: a) keeping a table of objects already copied during the current
copying pass b) letting user-defined classes override the copying operation or the
set of components copied This version does not copy types like module, class, function, method,
nor stack trace, stack frame, nor file, socket, window, nor array, nor
any similar types. Classes can use the same interfaces to control copying that they use
to control pickling: they can define methods called __getinitargs__(),
__getstate__() and __setstate__(). See the documentation for module
"pickle" for information on these methods.
""" import types
import weakref
from copyreg import dispatch_table
import builtins class Error(Exception):
pass
error = Error # backward compatibility try:
from org.python.core import PyStringMap
except ImportError:
PyStringMap = None __all__ = ["Error", "copy", "deepcopy"] def copy(x):
"""Shallow copy operation on arbitrary Python objects. See the module's __doc__ string for more info.
""" cls = type(x) copier = _copy_dispatch.get(cls)
if copier:
return copier(x) try:
issc = issubclass(cls, type)
except TypeError: # cls is not a class
issc = False
if issc:
# treat it as a regular class:
return _copy_immutable(x) copier = getattr(cls, "__copy__", None)
if copier:
return copier(x) reductor = dispatch_table.get(cls)
if reductor:
rv = reductor(x)
else:
reductor = getattr(x, "__reduce_ex__", None)
if reductor:
rv = reductor(4)
else:
reductor = getattr(x, "__reduce__", None)
if reductor:
rv = reductor()
else:
raise Error("un(shallow)copyable object of type %s" % cls) return _reconstruct(x, rv, 0) _copy_dispatch = d = {} def _copy_immutable(x):
return x
for t in (type(None), int, float, bool, str, tuple,
bytes, frozenset, type, range,
types.BuiltinFunctionType, type(Ellipsis),
types.FunctionType, weakref.ref):
d[t] = _copy_immutable
t = getattr(types, "CodeType", None)
if t is not None:
d[t] = _copy_immutable
for name in ("complex", "unicode"):
t = getattr(builtins, name, None)
if t is not None:
d[t] = _copy_immutable def _copy_with_constructor(x):
return type(x)(x)
for t in (list, dict, set):
d[t] = _copy_with_constructor def _copy_with_copy_method(x):
return x.copy()
if PyStringMap is not None:
d[PyStringMap] = _copy_with_copy_method del d def deepcopy(x, memo=None, _nil=[]):
"""Deep copy operation on arbitrary Python objects. See the module's __doc__ string for more info.
""" if memo is None:
memo = {} d = id(x)
y = memo.get(d, _nil)
if y is not _nil:
return y cls = type(x) copier = _deepcopy_dispatch.get(cls)
if copier:
y = copier(x, memo)
else:
try:
issc = issubclass(cls, type)
except TypeError: # cls is not a class (old Boost; see SF #502085)
issc = 0
if issc:
y = _deepcopy_atomic(x, memo)
else:
copier = getattr(x, "__deepcopy__", None)
if copier:
y = copier(memo)
else:
reductor = dispatch_table.get(cls)
if reductor:
rv = reductor(x)
else:
reductor = getattr(x, "__reduce_ex__", None)
if reductor:
rv = reductor(4)
else:
reductor = getattr(x, "__reduce__", None)
if reductor:
rv = reductor()
else:
raise Error(
"un(deep)copyable object of type %s" % cls)
y = _reconstruct(x, rv, 1, memo) # If is its own copy, don't memoize.
if y is not x:
memo[d] = y
_keep_alive(x, memo) # Make sure x lives at least as long as d
return y _deepcopy_dispatch = d = {} def _deepcopy_atomic(x, memo):
return x
d[type(None)] = _deepcopy_atomic
d[type(Ellipsis)] = _deepcopy_atomic
d[int] = _deepcopy_atomic
d[float] = _deepcopy_atomic
d[bool] = _deepcopy_atomic
try:
d[complex] = _deepcopy_atomic
except NameError:
pass
d[bytes] = _deepcopy_atomic
d[str] = _deepcopy_atomic
try:
d[types.CodeType] = _deepcopy_atomic
except AttributeError:
pass
d[type] = _deepcopy_atomic
d[range] = _deepcopy_atomic
d[types.BuiltinFunctionType] = _deepcopy_atomic
d[types.FunctionType] = _deepcopy_atomic
d[weakref.ref] = _deepcopy_atomic def _deepcopy_list(x, memo):
y = []
memo[id(x)] = y
for a in x:
y.append(deepcopy(a, memo))
return y
d[list] = _deepcopy_list def _deepcopy_tuple(x, memo):
y = [deepcopy(a, memo) for a in x]
# We're not going to put the tuple in the memo, but it's still important we
# check for it, in case the tuple contains recursive mutable structures.
try:
return memo[id(x)]
except KeyError:
pass
for k, j in zip(x, y):
if k is not j:
y = tuple(y)
break
else:
y = x
return y
d[tuple] = _deepcopy_tuple def _deepcopy_dict(x, memo):
y = {}
memo[id(x)] = y
for key, value in x.items():
y[deepcopy(key, memo)] = deepcopy(value, memo)
return y
d[dict] = _deepcopy_dict
if PyStringMap is not None:
d[PyStringMap] = _deepcopy_dict def _deepcopy_method(x, memo): # Copy instance methods
return type(x)(x.__func__, deepcopy(x.__self__, memo))
_deepcopy_dispatch[types.MethodType] = _deepcopy_method def _keep_alive(x, memo):
"""Keeps a reference to the object x in the memo. Because we remember objects by their id, we have
to assure that possibly temporary objects are kept
alive by referencing them.
We store a reference at the id of the memo, which should
normally not be used unless someone tries to deepcopy
the memo itself...
"""
try:
memo[id(memo)].append(x)
except KeyError:
# aha, this is the first one :-)
memo[id(memo)]=[x] def _reconstruct(x, info, deep, memo=None):
if isinstance(info, str):
return x
assert isinstance(info, tuple)
if memo is None:
memo = {}
n = len(info)
assert n in (2, 3, 4, 5)
callable, args = info[:2]
if n > 2:
state = info[2]
else:
state = {}
if n > 3:
listiter = info[3]
else:
listiter = None
if n > 4:
dictiter = info[4]
else:
dictiter = None
if deep:
args = deepcopy(args, memo)
y = callable(*args)
memo[id(x)] = y if state:
if deep:
state = deepcopy(state, memo)
if hasattr(y, '__setstate__'):
y.__setstate__(state)
else:
if isinstance(state, tuple) and len(state) == 2:
state, slotstate = state
else:
slotstate = None
if state is not None:
y.__dict__.update(state)
if slotstate is not None:
for key, value in slotstate.items():
setattr(y, key, value) if listiter is not None:
for item in listiter:
if deep:
item = deepcopy(item, memo)
y.append(item)
if dictiter is not None:
for key, value in dictiter:
if deep:
key = deepcopy(key, memo)
value = deepcopy(value, memo)
y[key] = value
return y del d del types # Helper for instance creation without calling __init__
class _EmptyClass:
pass

copy

 #!/usr/bin/env python
# -*-coding:utf-8-*-
# Author: Jason Wang
if __name__ == '__main__':
import copy
# 浅拷贝
# copy.copy()
# 深拷贝
# copy.deepcopy()
# 赋值
# =
# 数字和字符串的浅拷贝、深拷贝、和赋值都是引用的相同的内存地址
a1 = 123123
a2 = 123123
print("id a1:",id(a1))
print("id a2:",id(a2)) a1 = 234234
a2 = a1
print("id a1:",id(a1))
print("id a2:",id(a2)) a3 = copy.copy(a1)
print("id a3:",id(a3)) a4 = copy.deepcopy(a1)
print("id a4:",id(a4)) n1 = {"k1":"abc", "k2":123, "k3":["abc", 123]}
n2 = n1
print("id n1:",id(n1))
print("id n2:",id(n2))
n3 = copy.copy(n1)
print("id n3:",id(n3))
n4 = copy.deepcopy(n1)
print("id n4:",id(n4))
print("id n1['k3']:",id(n1['k3']))
print("id n2['k3']:",id(n2['k3']))
print("id n3['k3']:",id(n3['k3']))
print("id n4['k3']:",id(n4['k3'])) n3['k3'][0] = 'def'
print("n1['k3']",n1['k3'])
print("n2['k3']",n2['k3'])
print("n3['k3']",n3['k3'])
print("n4['k3']",n4['k3']) dic = {
"cpu":[80], }

copy test

##copy test output

id a1: 4330261904
id a2: 4330261904
id a1: 4329590608
id a2: 4329590608
id a3: 4329590608
id a4: 4329590608
id n1: 4330219144
id n2: 4330219144
id n3: 4332198600
id n4: 4332196616
id n1['k3']: 4332626760
id n2['k3']: 4332626760
id n3['k3']: 4332626760
id n4['k3']: 4332592968
n1['k3'] ['def', 123]
n2['k3'] ['def', 123]
n3['k3'] ['def', 123]
n4['k3'] ['abc', 123]

import json
li = [11,22,33]
json.dump(li,open('db','w'))#序列化
li = json.load(open('db','r'))##将字符产反序列化,读文件
print(type(li),li)
#<class 'list'> [11, 22, 33]


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