字典类型

字典类型以键值对的形式存储多个值

fruits = {'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
print(fruits)
print(type(fruits))
print(len(fruits))
print(fruits['apple'])
print(fruits['banana'])
print(fruits['carrot'])

{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
<class 'dict'>
3
苹果
香蕉
萝卜

如类型名所示，使用方法类似于字典，输入键查询值

操作

键值对的追加

fruits = {'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
print(fruits)
fruits['durian'] = '榴莲'
print(fruits)

{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜', 'durian': '榴莲'}

值的变更

fruits = {'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
print(fruits)
fruits['carrot'] = '人参'
print(fruits)

{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}
{'apple': '苹果', 'banana': '香蕉', 'carrot': '人参'}

键值对的削除

fruits = {'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜', 'durian': '榴莲'}
print(fruits)
del fruits['durian']
print(fruits)

{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜', 'durian': '榴莲'}
{'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜'}

键查找

fruits = {'apple': '苹果', 'banana': '香蕉', 'carrot': '萝卜', 'durian': '榴莲'}
target = 'egg'
if target in fruits:
    print('字典含键%s' % target)
else:
    print('字典不含键%s' % target)

字典不含键egg

取键值对

基本形式

for 键参数, 值参数 in 字典名.items():
    处理语句

如

n = {'apple': '苹果',
     'banana': '香蕉',
     'carrot': '萝卜',
     'durian': '榴莲'}
i = 1
for a, b in n.items():
    print(a, b, '%d个' %i)
    i += 1

apple 苹果 1个
banana 香蕉 2个
carrot 萝卜 3个
durian 榴莲 4个

取键

基本形式

for 键参数 in 字典名.keys():
    处理语句

如

n = {'apple': '苹果',
     'banana': '香蕉',
     'carrot': '萝卜',
     'durian': '榴莲'}
i = 1
for a in n.keys():
    print(a, '%d个' %i)
    i += 1

apple 1个
banana 2个
carrot 3个
durian 4个

取值

n = {'apple': '苹果',
     'banana': '香蕉',
     'carrot': '萝卜',
     'durian': '榴莲'}
i = 1
for a in n.values():
    print(a, '%d个' %i)
    i += 1

苹果 1个
香蕉 2个
萝卜 3个
榴莲 4个