jython语言学习笔记

1.变量可以随便定义，不限制类型，不限制数值。开头空4个空格，使用def定义函数，可以嵌套，可以传参。

2.每个语句结束的时候没有分号。定义类的时候没有括号。在print语句的后面有格式转换时要加上% , for和while之后要加冒号,快捷键被我改成了CTRL+R  和D

Method	Description of Functionality
capitalize()	Returns a capitalized copy of string
center (width[,fill])	Returns a repositioned string with specified width and provide optional padding filler character
count(sub[,start[,end]])	Count the number of distinct times the substring occurs within the string
decode([encoding[,errors]])	Decodes and returns Unicode string
encode([encoding[,errors]])	Returns an encoded version of a string
endswith(suffix[,start[,end]])	Returns a boolean to state whether the string ends in a given pattern
expandtabs([tabsize])	Converts tabs within a string into spaces
find(sub[,start[,end]])	Returns the index of the position where the first occurrence of the given substring begins
index(sub[,start[,end])	Returns the index of the position where the first occurrence of the given substring begins. Raises a ValueError with the substring is not found.
isalnum()	Returns a boolean to state whether the string contain only alphabetic and numeric characters
isalpha()	Returns a boolean to state whether the string contains all alphabetic characters
isdigit()	Returns a boolean to state whether the string contains all numeric characters
islower()	Returns a boolean to state whether a string contains all lowercase characters
isspace()	Returns a boolean to state whether the string consists of all whitespace
istitle()	Returns a boolean to state whether the first character of each word in the string is capitalized
isupper()	Returns a boolean to state whether all characters within the string are uppercase
join(sequence)	Returns a copy of sequence joined together with the original string placed between each element
ljust(width[,fillchar])	Returns a string of the specified width along with a copy of the original string at the leftmost bit. (Optionally padding empty space with fillchar)
lower()	Returns a copy of the original string with  all characters in the string converted to lowercase
lstrip([chars])	Removes the first found characters in the string from the left that match the given characters. Also removes whitespace from the left. Whitespace removal is default when specified with no arguments.
partition(separator)	Returns a partitioned string starting from the left using the provided separator
replace(old,new[,count])	Returns a copy of the original string replacing the portion of string given in old with the portion given in new
rfind(sub[,start[,end]])	Searches string from right to left and finds the first occurrence of the given string and returns highest index where sub is found
rindex(sub[,start[,end]])	Searches string from right to left and finds the first occurrence of the given string and either returns highest index where sub is found or raises an exception
rjust(width[,fillchar])	Returns copy of string Aligned  to the right by width
rpartition(separator)	Returns a copy of stringPartitioned starting from the right using the provided separator object
rsplit([separator[,maxsplit]])	Returns list of words in string and splits the string from the right side and uses the given separator as a delimiter. If maxsplit is specified then at most maxsplit splits are done (from the right).
rstrip([chars])	Returns copy of string removing the first found characters in the string from the right that match those given. Also removes whitespace from the right when no argument is specified.
split([separator[,maxsplit]])	Returns a list of words in string and splits the string from the left side and uses the given separator as a delimiter.
splitlines([keepends])	Splits the string into a list of lines. Keepends denotes if newline delimiters are removed. Returns the list of lines in the string.
startswith(prefix[,start[,end]])	Returns a boolean to state whether the string starts with the given prefix
strip([chars])	Returns a copy of string with the given characters removed from the string. If no argument is specified then whitespace is removed.
swapcase()	Returns a copy of the string the case of each character in the string converted.
title()	Returns a copy of the string with the first character in each word uppercase.
translate(table[,deletechars])	Returns a copy of the string using the given character translation table to translate the string. All characters occurring in optional deletechars argument are removed.
upper()	Returns a copy of string with  all of the characters in the string converted to  uppercase
zfill(width)	Returns a numeric string padded  from the left with zeros for the specified width.

d	signed integer decimal
i	signed integer
o	unsigned octal
u	unsigned decimal
x	unsigned hexidecimal (lowercase)
X	unsigned hexidecimal (uppercase letters)
E	floating point exponential format (uppercase ‘E’)
e	floating point exponential format (lowercase ‘e’)
f	floating point decimal format (lowercase)
F	floating point decimal format (same as ‘f’)
g	floating point exponential format if exponent < -4, otherwise float
G	floating point exponential format (uppercase) if exponent < -4, otherwise float
c	single character
r	string (converts any python object using repr())
s	string (converts any python object using str())
%	no conversion, results in a percent (%) character if specified twice

3. jython中的string和java一样也是不可变的。

4. 一个滑片list是包含开始数字，不包含结束数字的。pop()的同时会remove. remove()操作只能删除第一个匹配的。

index	Returns the index of the first value in the list which matches a given value.
count	Returns the number of items in the list which equal a given value.
sort	Sorts the items contained within the list and returns the list
reverse	Reverses the order of the items contained within the list, and returns the list

5.数组与List的区别是，List是可以改变的，而数组是不可以改变的。

Method or Function	Description
len(dictionary)	Function that returns number of items within the given dictionary.
dictionary [key]	Returns the item from the dictionary that is associated with the given key.
dictionary[key] = value	Sets the associated item in the dictionary to the given value.
del dictionary[key]	Deletes the given key/value pair from the dictionary.
dictionary.clear()	Method that removes all items from the dictionary.
dictionary.copy()	Method that creates a shallow copy of the dictionary.
has_key(key)	Function that returns a boolean stating whether the dictionary contains the given key. (Deprecated in favor of using in’)
key in d	Returns a boolean stating whether the given key is found in the dictionary
key not in d	Returns a boolean stating whether the given key is not found in the dictionary
items()	Returns a list of tuples including a copy of the key/value pairs within the dictionary.
keys()	Returns the a list of keys within the dictionary.
update([dictionary2])	Updates dictionary with the key/value pairs from the given dictionary. Existing keys will be overwritten.
fromkeys(sequence[,value])	Creates a new dictionary with keys from the given sequence. The values will be set to the value given.
values()	Returns the values within the dictionary as a list.
get(key[, b])	Returns the value associated with the given key. If the key does not exist, then returns b.
setdefault(key[, b])	Returns the value associated with the given key. If the key does not exist, then  the key value is set to b (mydict[key] = b)
pop(key[, b])	Returns and removes the key/value pair associated with the given key. If the key does not exist then returns b.
popItem()	An arbitrary key/value pair is popped from the dictionary
iteritems()	Returns an iterator over the key/value pairs in the dictionary.
iterkeys()	Returns an iterator over the keys in the dictionary.
itervalues()	Returns an iterator over the values in the dictionary.

6. sets是无序的，而且也不能重复，dic是可以重复的，sets使用前必须要加入包  from sets import set

Method or Operation	Description
len(set)	Returns the number of elements in a given set
copy()	Returns a new shallow copy of the set
difference(set2)	Returns a new set that contains all elements that are in the calling set, but not in set2
intersection(set2)	Returns a new set that contains all elements that the calling set and set2 have in common
issubbset(set2)	Returns a Boolean stating whether all elements in calling set are also in set2
issuperset(set2)	Returns a Boolean stating whether all elements in set2 are contained in calling set
symmetric_difference(set2)	Returns a new set containing elements either from the calling set or set2 but not from both (set1 ^ set2)
x in set	Tests whether x is contained in the set, returns boolean
x not in set	Tests whether x is not contained in the set, returns boolean
union(set2)	Returns a new set containing elements that are contained in both the calling set and set2

Method or Operation	Description
add(item)	Adds an item to a set if it is not already in the set
clear()	Removes all items in a set
difference_update(set2)	Returns the set with all elements contained in set2 removed
discard(element)	Removes designated element from set if present
intersection_update(set2)	Returns the set keeping only those elements that are also in set2
pop()	Return an arbitrary element from the set
remove(element)	Remove element from set if present, if not then KeyError is raised
symmetric_difference_update(set2)	Replace the calling set with a set containing elements from either the calling set or set2 but not both, and return it
update(set2)	Returns set including all elements from set2

7. read()和readlines（）读出内容的格式是不一样的，如果当前的位置是在文件的末端必须要seek，不然读不出来内容。

8.在string和list中，不用创建迭代器，也可以使用for进行迭代。如果将一个不可改变的对象赋给另外一个变量，例如string和integer .那这个变量是这个string的copy，改变这个变量的值不会改变string. 如果将一个可改变的对象赋给另外一个变量，例如list.那这个变量是这个List的引用，也就是同一个东西，改变这个变量的值会同时改变list。如果要得到一个list(a)的copy，那么要import copy，同时使用b=copy.copy(a).但这样也仅仅是一个浅copy。也就是说，不同的对象，但是同一个引用，虽然b is a 为false。但是如果改变b的值，a也会同样的改变。如果非要使用deepcopy，那么就要import copy，然后b=copy.deepcopy(a),这样改变了b的值之后，a的值就不会改变了。