如何使用函数将列表相乘? [英] How do I multiply lists together using a function?

问题描述

如何使用函数在python中将列表相乘?这就是我所拥有的:

how do I multiply lists together in python using a function? This is what I have:

    list = [1, 2, 3, 4]
    def list_multiplication(list, value):
         mylist = []
         for item in list:
              for place in value:
               mylist.append(item*value)
    return mylist

所以我想用它来乘以list * list(1 * 1、2 * 2、3 * 3、4 * 4)

So I want to use this to multiply list*list (1*1, 2*2, 3*3, 4*4)

所以输出将是1、4、9和16.我将如何在python中执行此操作，其中第二个列表可能是什么? 谢谢

So the output would be 1, 4, 9, and 16. How would I do this in python where the 2nd list could be anything? Thanks

推荐答案

我最喜欢的方法是将mul运算符映射到两个列表上:

My favorite way is mapping the mul operator over the two lists:

from operator import mul

mul(2, 5)
#>>> 10

mul(3, 6)
#>>> 18

map(mul, [1, 2, 3, 4, 5], [6, 7, 8, 9, 10])
#>>> <map object at 0x7fc424916f50>

map(至少在Python 3中)返回生成器.因此，如果您想要一个列表，则应将其转换为一个列表:

map, at least in Python 3, returns a generator. Hence if you want a list you should cast it to one:

list(map(mul, [1, 2, 3, 4, 5], [6, 7, 8, 9, 10]))
#>>> [6, 14, 24, 36, 50]

但是到那时，对zip列表使用列表理解可能更有意义.

But by then it might make more sense to use a list comprehension over the zip'd lists.

[a*b for a, b in zip([1, 2, 3, 4, 5], [6, 7, 8, 9, 10])]
#>>> [6, 14, 24, 36, 50]

为了解释最后一个，zip([a,b,c], [x,y,z])给出了(生成器)[(a,x),(b,y),(c,z)].

To explain the last one, zip([a,b,c], [x,y,z]) gives (a generator that generates) [(a,x),(b,y),(c,z)].

for a, b in将每个(m,n)对解包"为变量a和b，然后将它们乘以a*b.

The for a, b in "unpacks" each (m,n) pair into the variables a and b, and a*b multiplies them.

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