【脚本语言系列】关于Python基础知识映射器和过滤器，你需要知道的事

如何使用映射器(Map)和过滤器(Filter)

如何使用映射器(Map)

# -*- coding:utf-8 -*-
items = [1, 2, 3, 4, 5]
squared = []
cubed = []
for i in items:
squared.append(i**2)
cubed.append(i**3)

print items, squared, cubed

[1, 2, 3, 4, 5] [1, 4, 9, 16, 25] [1, 8, 27, 64, 125]

# -*- coding:utf-8 -*-
items = [1, 2, 3, 4, 5]
squared = list(map(lambda x : x ** 2, items))
cubed = list(map(lambda x : x ** 3, items))
print items, squared, cubed

def pow2(x):
return x*x
def pow3(x):
return x*x*x
squared = list(map(lambda x : pow2(x), items))
cubed = list(map(lambda x : pow3(x), items))
print items, squared, cubed

print "\n"

funcs = [pow2, pow3]
for i in range(5):
value = list(map(lambda x: x(i), funcs))
print value

[1, 2, 3, 4, 5] [1, 4, 9, 16, 25] [1, 8, 27, 64, 125][1, 2, 3, 4, 5] [1, 4, 9, 16, 25] [1, 8, 27, 64, 125]
[0, 0]
[1, 1]
[4, 8]
[9, 27]
[16, 64]

如何使用过滤器(Filter)

# -*- coding:utf-8 -*-
items = range(-5, 5)
lt_zero = list(filter(lambda x: x < 0, items))
print lt_zero

[-5, -4, -3, -2, -1]

什么是映射器(Map)和过滤器(Filter)

为何使用映射器(Map)和过滤器(Filter)