字典与元组

 

Dictionaries have a method called items that returns a sequence of tuples, where each tuple is a key-value pair.

>>> d = {'a':0, 'b':1, 'c':2}
>>> t = d.items()
>>> t
dict_items([('c', 2), ('a', 0), ('b', 1)])

The result is a dict_items object, which is an iterator that iterates the key-value pairs. You can use it in a for loop like this:

>>> for key, value in d.items(): ... print(key, value)
...
c 2
a 0 
b 1
Going in the other direction, you can use a list of tuples to initialize a new dictionary:
>>> t = [('a', 0), ('c', 2), ('b', 1)]
>>> d = dict(t)
>>> d
{'a': 0, 'c': 2, 'b': 1}
Combining dict with zip yields a concise way to create a dictionary:
>>> d = dict(zip('abc', range(3)))
>>> d
{'a': 0, 'c': 2, 'b': 1}

 

 

posted @ 2018-12-18 11:36  anobscureretreat  阅读(128)  评论(0编辑  收藏  举报