Python数据类型详解四字典：dict

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,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,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,**kwargs): # real signature unkNown
    """ Delete self[key]. """
    pass

  def __eq__(self,**kwargs): # real signature unkNown
    """ Return self==value. """
    pass

  def __getattribute__(self,**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,**kwargs): # real signature unkNown
    """ Return self>=value. """
    pass

  def __gt__(self,**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,**kwargs): # real signature unkNown
    """ Implement iter(self). """
    pass

  def __len__(self,**kwargs): # real signature unkNown
    """ Return len(self). """
    pass

  def __le__(self,**kwargs): # real signature unkNown
    """ Return self<=value. """
    pass

  def __lt__(self,**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,**kwargs): # real signature unkNown
    """ Return self!=value. """
    pass

  def __repr__(self,**kwargs): # real signature unkNown
    """ Return repr(self). """
    pass

  def __setitem__(self,**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

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

#如果没有key，会报错
user_info = {
  "name" :'zhangyanlin',"age" :18,"job" :'pythoner'
}
print(user_info['name'])

五.for循环

#循环
user_info = {
  0 :"zhangyanlin",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)

以上就是本文的全部内容了，希望对大家熟练掌握Python数据结构能够有所帮助。