Python遍历字典

1.遍历key值

1 >>> d = {'Python':'astonishing', 'C++':'complicated', 'Java':'versatile'}
2 >>> for key in d:
3 ...     print(key + ':' + d[key])
4 ...
5 Python:astonishing
6 C++:complicated
7 Java:versatile

同理，可把下列代码的d改为d.keys()

notice:python2除了上述两种方法外，还可以写为d.iterkeys()

2.遍历value值

1 >>> for value in d:
2 ...     print(value)
3 ...
4 Python
5 C++
6 Java

同理，可把下列代码的d改为d.values()

notice:python2除了上述两种方法外，还可以写为d.itervalues()

3.遍历字典

 1 >>> for kv in d.items():
 2 ...     print(kv)
 3 ...
 4 ('Python', 'astonishing')
 5 ('C++', 'complicated')
 6 ('Java', 'versatile')
 7 >>> for k, v in d.items():#开始偷懒，缩写k, v
 8 ...     print(k + ':' + v)
 9 ...
10 Python:astonishing
11 C++:complicated
12 Java:versatile

其实还有一种方法，用到了zip(元素对)使得我们可以像c/c++等语言一样循环两个变量

1 >>> for k, v in zip(d.keys(), d.values()):
2 ...     print(k + ':' + v)
3 ...
4 Python:astonishing
5 C++:complicated
6 Java:versatile

关于zip的用法，详见python cookbook:https://python3-cookbook.readthedocs.io/zh_CN/latest/c04/p11_iterate_over_multiple_sequences_simultaneously.html