Python中的字典与成员运算符初步探究

python/' target='_blank'>python元字典
字典(dictionary)是除列表以外Python之中最灵活的内置数据结构类型。列表是有序的对象结合，字典是无序的对象集合。
两者之间的区别在于：字典当中的元素是通过键来存取的，而不是通过偏移存取。
字典用"{ }"标识。字典由索引(key)和它对应的值value组成。

#!/usr/bin/python# -*- coding: UTF-8 -*-dict = {}dict['one'] = "This is one"dict[2] = "This is two"tinydict = {'name': 'john','code':6734, 'dept': 'sales'}print dict['one'] # 输出键为'one' 的值print dict[2] # 输出键为 2 的值print tinydict # 输出完整的字典print tinydict.keys() # 输出所有键print tinydict.values() # 输出所有值

输出结果为：

This is one This is two {'dept': 'sales', 'code': 6734, 'name': 'john'} ['dept', 'code', 'name'] ['sales', 6734, 'john']

Python成员运算符
除了以上的一些运算符之外，Python还支持成员运算符，测试实例中包含了一系列的成员，包括字符串，列表或元组。

以下实例演示了Python所有成员运算符的操作：

#!/usr/bin/pythona = 10b = 20list = [1, 2, 3, 4, 5 ];if ( a in list ):  print "Line 1 - a is available in the given list"else:  print "Line 1 - a is not available in the given list"if ( b not in list ):  print "Line 2 - b is not available in the given list"else:  print "Line 2 - b is available in the given list"a = 2if ( a in list ):  print "Line 3 - a is available in the given list"else:  print "Line 3 - a is not available in the given list"

以上实例输出结果：

Line 1 - a is not available in the given listLine 2 - b is not available in the given listLine 3 - a is available in the given list