Contents

• 字典推导式

  • 语法：

    • 代码示例1

    • 代码示例2

5.2. 字典推导式

快速生成一个字典，进行调整键值位置、赛选等操作

5.2.1. 语法：

{ key_expression : value_expression  for expression  in iterable  }

{ key:value for 循环 }

代码示例1

#!/usr/bin/env python
#-*- coding:utf8 -*-
import random
randomdict = {i:random.randint(10, 100) for i in range(1, 5)}
print(randomdict)
print()

name = ["hujianli","xiaojian","jianlihu","mengxi"]
xingzhuo = ["水瓶座","射手座","天蝎座","处女座"]
dict1 = {i:a for i,a in zip(name,xingzhuo)}
print(dict1)

print()

D = { k:v for (k,v) in zip(["q","b","d"],[1,2,3]) }
print(D)

D1 = { x:x**2 for x in range(1,5) }
print(D1)

D = {c: c * 4 for c in 'SPAM'}
print(D)


D = {c.lower(): c + '!' for c in ['SPAM', 'EGGS', 'HAM']}
print(D)

#利用字典推导式把字典的key和value做转换：{key:value}变成{value:key}的形式
# 字典推导式的用法
my_dict = {'derek1':11,'derek2':22,'derek3':33}
reversed_dict = {value:key for key,value in my_dict.items()}
print(reversed_dict)    #{11: 'derek1', 22: 'derek2', 33: 'derek3'}

代码示例2

#字典推导式
keys = ["name","age","weight"]
values = ["hujianli",21,120]
dic_tuidao = {k:v for k,v in zip(keys,values)}
print(dic_tuidao)

prices = {
    'ACME': 45.23,
    'AAPL': 612.78,
    'IBM': 205.55,
    'HPQ': 37.20,
    'FB': 10.75
}

p1 = {key:value for key,value in prices.items() if value > 200}
print(p1)
tech_name = {'AAPL', 'IBM', 'HPQ', 'MSFT'}
p2 = {key:value for key,value in prices.items() if key in tech_name}
print(p2)

eg

input_dict = {"one": 1, "tow": 2, "three": 3, "four": 4}
out_dict = {k: v for k, v in input_dict.items() if v % 2 == 0}
print(out_dict)

out_dict2 = {k for k, v in input_dict.items() if v % 2 == 0}
print(out_dict2)