在Python中创建一个新的dict

7 回答

• 3

  d = dict()
  

  要么

  d = {}
  

  要么

  import types
  d = types.DictType.__new__(types.DictType, (), {})
  

  回复于 2024-04-24T23:55:54+08:00
• 13

  所以有两种方法可以创建一个dict：

  • my_dict = dict()

  • my_dict = {}

  但是在这两个选项中， {} 比 dict() 更有效 . CHECK HERE

  回复于 2024-04-24T23:55:54+08:00
• 1

  你可以这样做

  x = {}
  x['a'] = 1
  

  回复于 2024-04-24T23:55:54+08:00
• 180

  >>> dict.fromkeys(['a','b','c'],[1,2,3])
  
  
  {'a': [1, 2, 3], 'b': [1, 2, 3], 'c': [1, 2, 3]}
  

  回复于 2024-04-24T23:55:54+08:00
• 490

  知道如何编写预设字典也很有用：

  cmap =  {'US':'USA','GB':'Great Britain'}
  
  def cxlate(country):
      try:
          ret = cmap[country]
      except:
          ret = '?'
      return ret
  
  present = 'US' # this one is in the dict
  missing = 'RU' # this one is not
  
  print cxlate(present) # == USA
  print cxlate(missing) # == ?
  
  # or, much more simply as suggested below:
  
  print cmap.get(present,'?') # == USA
  print cmap.get(missing,'?') # == ?
  
  # with country codes, you might prefer to return the original on failure:
  
  print cmap.get(present,present) # == USA
  print cmap.get(missing,missing) # == RU
  

  回复于 2024-04-24T23:55:54+08:00
• 20

  >>> dict(a=2,b=4)
  {'a': 2, 'b': 4}
  

  将在python字典中添加值 .

  回复于 2024-04-24T23:55:54+08:00
• 12

  不带参数调用 dict

  new_dict = dict()
  

  或者简单地写

  new_dict = {}
  

  回复于 2024-04-24T23:55:54+08:00