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=(), /)
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| Built-in immutable sequence.
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| If no argument is given, the constructor returns an empty tuple.
| If iterable is specified the tuple is initialized from iterable's items.
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| If the argument is a tuple, the return value is the same object.
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| Methods defined here:
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| __add__(self, value, /)
| Return self+value.
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| __contains__(self, key, /)
| Return key in self.
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| __eq__(self, value, /)
| Return self==value.
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| __ge__(self, value, /)
| Return self>=value.
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| __getattribute__(self, name, /)
| Return getattr(self, name).
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| __getitem__(self, key, /)
| Return self[key].
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| __getnewargs__(self, /)
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| __gt__(self, value, /)
| Return self>value.
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| __hash__(self, /)
| Return hash(self).
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| __iter__(self, /)
| Implement iter(self).
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| __le__(self, value, /)
| Return self<=value.
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| __len__(self, /)
| Return len(self).
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| __lt__(self, value, /)
| Return self<value.
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| __mul__(self, value, /)
| Return self*value.
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| __ne__(self, value, /)
| Return self!=value.
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| __repr__(self, /)
| Return repr(self).
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| __rmul__(self, value, /)
| Return value*self.
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| count(self, value, /)
| Return number of occurrences of value.
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| index(self, value, start=0, stop=9223372036854775807, /)
| Return first index of value.
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| Raises ValueError if the value is not present.
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| ----------------------------------------------------------------------
| Static methods defined here:
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| __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
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| Build an unordered collection of unique elements.
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| Methods defined here:
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| __and__(self, value, /)
| Return self&value.
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| __contains__(...)
| x.__contains__(y) <==> y in x.
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| __eq__(self, value, /)
| Return self==value.
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| __ge__(self, value, /)
| Return self>=value.
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| __getattribute__(self, name, /)
| Return getattr(self, name).
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| __gt__(self, value, /)
| Return self>value.
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| __iand__(self, value, /)
| Return self&=value.
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| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
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| __ior__(self, value, /)
| Return self|=value.
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| __isub__(self, value, /)
| Return self-=value.
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| __iter__(self, /)
| Implement iter(self).
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| __ixor__(self, value, /)
| Return self^=value.
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| __le__(self, value, /)
| Return self<=value.
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| __len__(self, /)
| Return len(self).
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| __lt__(self, value, /)
| Return self<value.
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| __ne__(self, value, /)
| Return self!=value.
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| __or__(self, value, /)
| Return self|value.
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| __rand__(self, value, /)
| Return value&self.
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| __reduce__(...)
| Return state information for pickling.
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| __repr__(self, /)
| Return repr(self).
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| __ror__(self, value, /)
| Return value|self.
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| __rsub__(self, value, /)
| Return value-self.
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| __rxor__(self, value, /)
| Return value^self.
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| __sizeof__(...)
| S.__sizeof__() -> size of S in memory, in bytes
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| __sub__(self, value, /)
| Return self-value.
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| __xor__(self, value, /)
| Return self^value.
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| add(...)
| Add an element to a set.
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| This has no effect if the element is already present.
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| clear(...)
| Remove all elements from this set.
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| copy(...)
| Return a shallow copy of a set.
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| difference(...)
| Return the difference of two or more sets as a new set.
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| (i.e. all elements that are in this set but not the others.)
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| difference_update(...)
| Remove all elements of another set from this set.
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| discard(...)
| Remove an element from a set if it is a member.
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| If the element is not a member, do nothing.
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| intersection(...)
| Return the intersection of two sets as a new set.
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| (i.e. all elements that are in both sets.)
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| intersection_update(...)
| Update a set with the intersection of itself and another.
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| isdisjoint(...)
| Return True if two sets have a null intersection.
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| issubset(...)
| Report whether another set contains this set.
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| issuperset(...)
| Report whether this set contains another set.
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| pop(...)
| Remove and return an arbitrary set element.
| Raises KeyError if the set is empty.
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| remove(...)
| Remove an element from a set; it must be a member.
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| If the element is not a member, raise a KeyError.
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| symmetric_difference(...)
| Return the symmetric difference of two sets as a new set.
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| (i.e. all elements that are in exactly one of the sets.)
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| symmetric_difference_update(...)
| Update a set with the symmetric difference of itself and another.
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| union(...)
| Return the union of sets as a new set.
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| (i.e. all elements that are in either set.)
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| update(...)
| Update a set with the union of itself and others.
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| ----------------------------------------------------------------------
| 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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