python基础知识之字典(Dict)

作者:51码银 时间:2023-08-25 20:01:44 

 一、字典的基本操作

1.定义字典 

字典也是一个列表型的数据结构,字典的数据是用“{ }”装的(列表:[ ],元组:( )),字典的元素是一一对应的关系“key-value”。

格式:

Dictname={ key1:value1,...,key2:value2}    

#value是任何的python的对象

#字典的元素数量也是用len()函数

多说无益,直接看例子比较清晰:

实例: 

flower={'rose':10,'orchid':16,'carnation':8}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40}
print(flower)
print(tea)
print("字典flower的元素数量是:",len(flower))
print("字典的数据类型:",type(tea))

python基础知识之字典(Dict)

2.建立空字典

实例:

print("``````````````````````````````````````````````````````````")
flower={}
flower['rose']=13
flower['orchid']=16
print(flower)
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

3.列出字典元素的值 

格式:

flower【'rose'】

#注意列出字典元素的值要用中括号哦“[ ]”

#上面语句表达的意思是字典 flower 的 rose(key)的对应 10(value)值。

实例: 

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40}
print("一支玫瑰的价钱是:",flower['rose'])
print("红茶一袋的价钱是:",tea['红茶'])
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

如果有两个“rose”,两个“红茶”呢,元素对应的值(value)是哪个呢?

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8,'rose':15}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40,'红茶':13}
print("一支玫瑰的价钱是:",flower['rose'])
print("红茶一袋的价钱是:",tea['红茶'])
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

如上所示,字典中的元素对应值被后面的值占领了。 

4.增加字典元素 

实例:

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40}
flower['tuilp']=13
print(flower)

print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

 5.更改元素内容

实例:

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40}
flower['rose']=13
print(flower)
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

6.删除字典(特定元素)

删除元素实例: 

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
tea={'红茶':30,'绿茶':20,'茉莉花茶':40}
del flower['rose']
print(flower)
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

 删除字典实例:

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
del flower
print(flower)
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

7. 字典的复制

print("``````````````````````````````````````````````````````````")
flower={'rose':10,'orchid':16,'carnation':8}
copyflower=flower.copy()
print(flower)
print(copyflower)
print("``````````````````````````````````````````````````````````")

python基础知识之字典(Dict)

 二、遍历字典

1.遍历字典的key-value

flower={'rose':10,
'orchid':16,
'carnation':8}
for flowers,price in flower.items():
print("花名:",flowers)
print("价格:",price)
print("\n")

python基础知识之字典(Dict)

2.遍历字典的键(key) 

flower={'rose':10,
'orchid':16,
'carnation':8}
for flowers in flower.keys():
print("花名:",flowers)
print("\n")

python基础知识之字典(Dict)

没有keys()函数也行:

flower={'rose':10,
'orchid':16,
'carnation':8}
for flowers in flower:
print("花名:",flowers)

python基础知识之字典(Dict)

 3.遍历字典的值(value)

flower={'rose':10,
'orchid':16,
'carnation':8}
for flowers in flower.values():
print("价格:",flowers)

python基础知识之字典(Dict)

 4.字典里面放字典

实例:人物介绍

role={

'鲁班':{
'技能':'土木建筑',
'职业':'工匠'
},
'钟无艳':{
'技能':'出谋划策',
'职业':'中国古代四大丑女之一'
},
'蔡文姬':{
'技能':'琴棋书画',
'职业':'董祀之妻'
}

}
for a,b in role.items():
print("姓名:",a)
print("介绍:",b)

python基础知识之字典(Dict)

三、简单介绍下函数

len():求元素个数

get():搜寻字典的key

格式:返回值=字典名.get('key')

pop():删除元素

格式:返回值=字典名.pop('key')

来源:https://blog.51cto.com/hwuu/6064023

标签:ython,字典,Dict
0
投稿

猜你喜欢

  • MySQL8下忘记密码后重置密码的办法(MySQL老方法不灵了)

    2024-01-17 11:38:49
  • 学习Python3 Dlib19.7进行人脸面部识别

    2022-03-18 00:01:30
  • pycharm配置QtDesigner的超详细方法

    2022-09-07 13:35:01
  • js获取 type=radio 值的方法

    2024-04-29 13:18:38
  • 深入研究ASP中的Session

    2007-09-13 12:37:00
  • Node.js API详解之 Error模块用法实例分析

    2024-05-13 09:58:47
  • php输出xml必须header的解决方法

    2023-09-11 20:00:16
  • Vue 实现穿梭框功能的详细代码

    2024-05-09 10:51:53
  • VBScript中LBound函数和UBound函数的用法

    2008-06-27 13:02:00
  • Python面向对象之继承原理与用法案例分析

    2021-06-28 02:07:53
  • PHP中__LINE__,__FILE__,__DIR__等常用魔术常量实例讲解

    2023-06-13 23:42:32
  • 如何利用Image Data Type在主页中显示图形?

    2010-01-01 15:13:00
  • python查看数据类型的方法

    2021-11-12 03:42:17
  • mysql数据库密码忘记解决方法

    2024-01-16 11:52:23
  • asp如何分页显示数据库查询结果?

    2009-11-22 19:23:00
  • 7个好用的TypeScript新功能

    2024-04-23 09:04:00
  • Python reduce函数作用及实例解析

    2023-10-10 22:27:47
  • 交互设计模式——分页

    2009-07-30 13:00:00
  • Go语言使用defer+recover解决panic导致程序崩溃的问题

    2024-01-30 06:29:18
  • 利用python爬取斗鱼app中照片方法实例

    2022-01-03 17:40:39
  • asp之家 网络编程 m.aspxhome.com