Python - 字典(dict) 详解 及 代码
字典(dict) 详解 及 代码
本文地址: http://blog.csdn.net/caroline_wendy/article/details/17291329
字典(dict)是表示映射的数据结构,key-value形式, key必须是唯一的;
items()方法, 返回字典的所有项;
可以通过for循环去遍历字典的键(key)和值(value), 也可以使用if判断元素是否存在;
可以通过len()求字典的长度;下标操作符("[]")增加和删除元素;
代码:
# -*- coding: utf-8 -*- #==================== #File: abop.py #Author: Wendy #Date: 2013-12-03 #==================== #eclipse pydev, python3.3 #字典, 即map, dict an = { 'Caroline' : 'A beautiful girl.', 'Wendy' : 'A talent girl.', 'Spike' : 'A good boy' } print (an) print ("Who is Caroline?", an['Caroline']) del an['Spike'] print('There are {0} girls.'.format(len(an))) for name, property in an.items() : #遍历字典的项 print('{0} is that {1}'.format(name, property)) an['Ruby'] = 'A pretty girl' if 'Ruby' in an : #判断元素是否存在 print("The new one Ruby is that", an['Ruby'])
输出:
{'Caroline': 'A beautiful girl.', 'Wendy': 'A talent girl.', 'Spike': 'A good boy'} Who is Caroline? A beautiful girl. There are 2 girls. Caroline is that A beautiful girl. Wendy is that A talent girl. The new one Ruby is that A pretty girl