Python數據類型詳解(四)字典:dict
更新時間:2016年05月12日 08:53:26 作者:aylin
本文給大家分享的知識是Python數據類型中的字典(dict)的基本概念,常用操作以及示例,非常的實用,對于大家理解字典dict非常有幫助,希望大家能夠喜歡
一.基本數據類型
整數:int
字符串:str(注:\t等于一個tab鍵)
布爾值: bool
列表:list
列表用[]
元祖:tuple
元祖用()
字典:dict
注:所有的數據類型都存在想對應的類列里,元祖和列表功能一樣,列表可以修改,元祖不能修改。
二.字典所有數據類型:
常用操作:
索引、新增、刪除、鍵、值、鍵值對、循環(huán)、長度
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.所有字典數據類型舉例
user_info = { 0 :"zhangyanlin", "age" :"18", 2 :"pythoner" } #獲取所有的key print(user_info.keys()) #獲取所有的values print(user_info.values()) #獲取所有的key和values print(user_info.items()) clear清除所有的內容 user_info.clear() print(user_info) #get 根據key獲取值,如果key不存在,可以指定一個默認值 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
#如果沒有key,會報錯 user_info = { "name" :'zhangyanlin', "age" :18, "job" :'pythoner' } print(user_info['name'])
五.for循環(huán)
#循環(huán) user_info = { 0 :"zhangyanlin", "age" :"18", 2 :"pythoner" } for i in user_info: print(i) #循環(huán)輸出所有的鍵入值 for k,v in user_info.items(): print(k) print(v)
以上就是本文的全部內容了,希望對大家熟練掌握Python數據結構能夠有所幫助。
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