Python数据类型之字典
一.基本数据类型
整数:int
字符串:str(注:\t等于一个tab键)
布尔值: bool
列表:list
列表用[]
元祖:tuple
元祖用()
字典:dict
注:所有的数据类型都存在想对应的类列里,元祖和列表功能一样,列表可以修改,元祖不能修改。
二.字典所有数据类型:
常用操作:
- 索引
- 新增
- 删除
- 键、值、键值对
- 循环
- 长度

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__ """ D.clear() -> None. Remove all items from D. """ pass def copy(self): # real signature unknown; restored from __doc__ """ D.copy() -> a shallow copy of D """ pass @staticmethod # known case def fromkeys(*args, **kwargs): # real signature unknown """ Returns a new dict with keys from iterable and values equal to value. """ pass def get(self, k, d=None): # real signature unknown; restored from __doc__ """ D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None. """ pass def items(self): # real signature unknown; restored from __doc__ """ D.items() -> a set-like object providing a view on D's items """ pass def keys(self): # real signature unknown; restored from __doc__ """ D.keys() -> a set-like object providing a view on D's keys """ pass def pop(self, k, d=None): # real signature unknown; restored from __doc__ """ 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__ """ 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__ """ 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 """ D.update([E, ]**F) -> None. Update D from dict/iterable E and F. If E is present and has a .keys() method, then does: for k in E: D[k] = E[k] If E is present and lacks a .keys() method, then 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__ """ D.values() -> an object providing a view on D's values """ pass def __contains__(self, *args, **kwargs): # real signature unknown """ True if D has a key k, else False. """ pass def __delitem__(self, *args, **kwargs): # real signature unknown """ Delete self[key]. """ pass def __eq__(self, *args, **kwargs): # real signature unknown """ Return self==value. """ pass def __getattribute__(self, *args, **kwargs): # real signature unknown """ Return getattr(self, name). """ pass def __getitem__(self, y): # real signature unknown; restored from __doc__ """ x.__getitem__(y) <==> x[y] """ pass def __ge__(self, *args, **kwargs): # real signature unknown """ Return self>=value. """ pass def __gt__(self, *args, **kwargs): # real signature unknown """ Return self>value. """ 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, *args, **kwargs): # real signature unknown """ Implement iter(self). """ pass def __len__(self, *args, **kwargs): # real signature unknown """ Return len(self). """ pass def __le__(self, *args, **kwargs): # real signature unknown """ Return self<=value. """ pass def __lt__(self, *args, **kwargs): # real signature unknown """ Return self<value. """ pass @staticmethod # known case of __new__ def __new__(*args, **kwargs): # real signature unknown """ Create and return a new object. See help(type) for accurate signature. """ pass def __ne__(self, *args, **kwargs): # real signature unknown """ Return self!=value. """ pass def __repr__(self, *args, **kwargs): # real signature unknown """ Return repr(self). """ pass def __setitem__(self, *args, **kwargs): # real signature unknown """ Set self[key] to value. """ pass def __sizeof__(self): # real signature unknown; restored from __doc__ """ D.__sizeof__() -> size of D in memory, in bytes """ pass __hash__ = None
三.所有字典数据类型举例
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 | user_info = { 0 : "zhangyanlin" , "age" : "18" , 2 : "pythoner" } #获取所有的key print (user_info.keys()) #获取所有的values print (user_info.values()) #获取所有的key和values print (user_info.items()) clear清除所有的内容 user_info.clear() print (user_info) #get 根据key获取值,如果key不存在,可以指定一个默认值 val = user_info.get( 'age' ) print (val) #update批量更新 test = { 'a' : 111 , 'b' : 222 } user_info.update(test) print (user_info) |
四.索引
1 2 3 4 5 6 7 | #如果没有key,会报错 user_info = { "name" : 'zhangyanlin' , "age" : 18 , "job" : 'pythoner' } print (user_info[ 'name' ]) |
五.for循环
1 2 3 4 5 6 7 8 9 10 11 12 13 | #循环 user_info = { 0 : "zhangyanlin" , "age" : "18" , 2 : "pythoner" } for i in user_info: print (i) #循环输出所有的键入值 for k,v in user_info.items(): print (k) print (v) |
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