15 数据结构

出处： 菜鸟教程 - Python3 数据结构

15.1 将列表当作队列使用

在列表的最后添加或者弹出元素速度快，然而在列表里插入或者从头部弹出速度却不快（因为所有其他的元素都得一个一个地移动）。

15.2 遍历技巧

遍历字典：

python 复制代码

>>> knights = {'gallahad': 'the pure', 'robin': 'the brave'}
>>> for k, v in knights.items():
...     print(k, v)
...
gallahad the pure
robin the brave

遍历列表：

python 复制代码

>>> for i, v in enumerate(['tic', 'tac', 'toe']):
...     print(i, v)
...
0 tic
1 tac
2 toe

遍历多个序列：

python 复制代码

>>> questions = ['name', 'quest', 'favorite color']
>>> answers = ['lancelot', 'the holy grail', 'blue']
>>> for q, a in zip(questions, answers):
...     print('What is your {0}?  It is {1}.'.format(q, a))
...
What is your name?  It is lancelot.
What is your quest?  It is the holy grail.
What is your favorite color?  It is blue.

反向遍历：

python 复制代码

>>> for i in reversed(range(1, 10, 2)):
...     print(i)
...
9
7
5
3
1