Python---基础---dict_tuple_set

2019-05-21

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help(tuple)

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Help on class tuple in module builtins:

class tuple(object)
|  tuple(iterable=(), /)
| 
|  Built-in immutable sequence.
| 
|  If no argument is given, the constructor returns an empty tuple.
|  If iterable is specified the tuple is initialized from iterable's items.
| 
|  If the argument is a tuple, the return value is the same object.
| 
|  Methods defined here:
| 
|  __add__(self, value, /)
|      Return self+value.
| 
|  __contains__(self, key, /)
|      Return key in self.
| 
|  __eq__(self, value, /)
|      Return self==value.
| 
|  __ge__(self, value, /)
|      Return self>=value.
| 
|  __getattribute__(self, name, /)
|      Return getattr(self, name).
| 
|  __getitem__(self, key, /)
|      Return self[key].
| 
|  __getnewargs__(self, /)
| 
|  __gt__(self, value, /)
|      Return self>value.
| 
|  __hash__(self, /)
|      Return hash(self).
| 
|  __iter__(self, /)
|      Implement iter(self).
| 
|  __le__(self, value, /)
|      Return self<=value.
| 
|  __len__(self, /)
|      Return len(self).
| 
|  __lt__(self, value, /)
|      Return self<value.
| 
|  __mul__(self, value, /)
|      Return self*value.
| 
|  __ne__(self, value, /)
|      Return self!=value.
| 
|  __repr__(self, /)
|      Return repr(self).
| 
|  __rmul__(self, value, /)
|      Return value*self.
| 
|  count(self, value, /)
|      Return number of occurrences of value.
| 
|  index(self, value, start=0, stop=9223372036854775807, /)
|      Return first index of value.
|     
|      Raises ValueError if the value is not present.
| 
|  ----------------------------------------------------------------------
|  Static methods defined here:
| 
|  __new__(*args, **kwargs) from builtins.type
|      Create and return a new object.  See help(type) for accurate signature.
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# count() 计算某个元素在元组中出现的次数
tuple1 = (3,2,4,1,3,6)
print(tuple1.count(3))

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# index() 获取值在元组中的索引
tuple1 = (3,2,4,1,3,6)
print(tuple1.index(3))
print(tuple1.index(3,1,5))

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# clear() 清除整个字典   返回None
dict1 = {'a':1, 'b':2, 'c':3}
dict2 = dict1.copy()
print(dict2)

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# fromkeys() 按照指定的序列为键创建字典，值都是一样的
list1 = ['a', 'b', 'c']
dict1 = {}.fromkeys(list1)
dict2 = {}.fromkeys(list1, 3)
print(dict1,dict2)

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# get() 根据键获取指定的值    找不到的键如果没有默认值则返回默认值， 如果没默认值，则返回None
dict1 = {'a':1, 'b':2, 'c':3}
print(dict1.get('b'))
print(dict1.get('d'))
print(dict1.get('d', 4))

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# items() 将字典变成类似于元组的形式方便遍历
dict1 = {'a':1, 'b':2, 'c':3}
for k,v in dict1.items():
    print(k,v)
for i in dict1.items():
    print(i)
   
print(dict1.items())

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# pop() 移除字典中指定元素  返回键所对应的值，如果键不存在，则返回默认值，如果键找不到，没有默认值，就会报错
dict1 = {'a':1, 'b':2, 'c':3}
print(dict1.pop('a'))
print(dict1)
print(dict1.pop('d', 4))
print(dict1.pop('d'))

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# popitem() 移除字典的键值时，返回移除的键和值
dict1 = {'d':4,'a':1, 'b':2, 'c':3 }
print(dict1.popitem())

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# update() 修改字典中的值
dict1 = {'d':4, 'a':1, 'b':2, 'c':3}
dict1.update({'a':3, 'b':4, 'e':6})
print(dict1)

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help(set)

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Help on class set in module builtins:

class set(object)
|  set() -> new empty set object
|  set(iterable) -> new set object
| 
|  Build an unordered collection of unique elements.
| 
|  Methods defined here:
| 
|  __and__(self, value, /)
|      Return self&value.
| 
|  __contains__(...)
|      x.__contains__(y) <==> y in x.
| 
|  __eq__(self, value, /)
|      Return self==value.
| 
|  __ge__(self, value, /)
|      Return self>=value.
| 
|  __getattribute__(self, name, /)
|      Return getattr(self, name).
| 
|  __gt__(self, value, /)
|      Return self>value.
| 
|  __iand__(self, value, /)
|      Return self&=value.
| 
|  __init__(self, /, *args, **kwargs)
|      Initialize self.  See help(type(self)) for accurate signature.
| 
|  __ior__(self, value, /)
|      Return self|=value.
| 
|  __isub__(self, value, /)
|      Return self-=value.
| 
|  __iter__(self, /)
|      Implement iter(self).
| 
|  __ixor__(self, value, /)
|      Return self^=value.
| 
|  __le__(self, value, /)
|      Return self<=value.
| 
|  __len__(self, /)
|      Return len(self).
| 
|  __lt__(self, value, /)
|      Return self<value.
| 
|  __ne__(self, value, /)
|      Return self!=value.
| 
|  __or__(self, value, /)
|      Return self|value.
| 
|  __rand__(self, value, /)
|      Return value&self.
| 
|  __reduce__(...)
|      Return state information for pickling.
| 
|  __repr__(self, /)
|      Return repr(self).
| 
|  __ror__(self, value, /)
|      Return value|self.
| 
|  __rsub__(self, value, /)
|      Return value-self.
| 
|  __rxor__(self, value, /)
|      Return value^self.
| 
|  __sizeof__(...)
|      S.__sizeof__() -> size of S in memory, in bytes
| 
|  __sub__(self, value, /)
|      Return self-value.
| 
|  __xor__(self, value, /)
|      Return self^value.
| 
|  add(...)
|      Add an element to a set.
|     
|      This has no effect if the element is already present.
| 
|  clear(...)
|      Remove all elements from this set.
| 
|  copy(...)
|      Return a shallow copy of a set.
| 
|  difference(...)
|      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.)
| 
|  difference_update(...)
|      Remove all elements of another set from this set.
| 
|  discard(...)
|      Remove an element from a set if it is a member.
|     
|      If the element is not a member, do nothing.
| 
|  intersection(...)
|      Return the intersection of two sets as a new set.
|     
|      (i.e. all elements that are in both sets.)
| 
|  intersection_update(...)
|      Update a set with the intersection of itself and another.
| 
|  isdisjoint(...)
|      Return True if two sets have a null intersection.
| 
|  issubset(...)
|      Report whether another set contains this set.
| 
|  issuperset(...)
|      Report whether this set contains another set.
| 
|  pop(...)
|      Remove and return an arbitrary set element.
|      Raises KeyError if the set is empty.
| 
|  remove(...)
|      Remove an element from a set; it must be a member.
|     
|      If the element is not a member, raise a KeyError.
| 
|  symmetric_difference(...)
|      Return the symmetric difference of two sets as a new set.
|     
|      (i.e. all elements that are in exactly one of the sets.)
| 
|  symmetric_difference_update(...)
|      Update a set with the symmetric difference of itself and another.
| 
|  union(...)
|      Return the union of sets as a new set.
|     
|      (i.e. all elements that are in either set.)
| 
|  update(...)
|      Update a set with the union of itself and others.
| 
|  ----------------------------------------------------------------------
|  Static methods defined here:
| 
|  __new__(*args, **kwargs) from builtins.type
|      Create and return a new object.  See help(type) for accurate signature.
| 
|  ----------------------------------------------------------------------
|  Data and other attributes defined here:
| 
|  __hash__ = None

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a = set()
print(a)
list1 = [1,2,3,4]
a = set(list1)
print(a)

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# add() 向集合中添加元素
set1 = {5,1,2,3,4,'b','u'}
set1.add(6)
print(set1)

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# clear()   清空集合
# copy()   复制集合
# pop()    随机弹出一个元素
a = {'a', 'b', 'f', 4}
a.pop()
print(a)

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# remove 删除集合中的某个值，如果这个值不在集合中会报错
a = {'a', 'b', 'f', 4}
a.remove(4)
print(a)
a.remove(4)

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# difference() 差集
# difference_update() 区别就是第一个返回一个新的集合，第二个把原来集合覆盖
set1 = {1,2,3,4,7}
set2 = {2,4,8,111,24}
set3 = set1.difference(set2)
print(set3)
print(set1)

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