替代在 Python 中嵌套 for 循环 [英] Alternative to nesting for loops in Python

问题描述

我读到 Python 的一个关键信念是扁平 > 嵌套.但是，如果我有几个变量在计数，那么多个 for 循环的替代方法是什么?我的代码用于计算网格总和，如下所示:

I've read that one of the key beliefs of Python is that flat > nested. However, if I have several variables counting up, what is the alternative to multiple for loops? My code is for counting grid sums and goes as follows:

def horizontal():
    for x in range(20):
        for y in range(17):
            temp = grid[x][y: y + 4]
            sum = 0
            for n in temp:
                sum += int(n)
            print sum # EDIT: the return instead of print was a mistype

在我看来，它嵌套过多.首先，Python 中的许多嵌套循环被认为是什么(我之前肯定见过 2 个嵌套循环).其次，如果嵌套过多，那么编写此代码的替代方法是什么?

This seems to me like it is too heavily nested. Firstly, what is considered to many nested loops in Python ( I have certainly seen 2 nested loops before). Secondly, if this is too heavily nested, what is an alternative way to write this code?

推荐答案

from itertools import product

def horizontal():
    for x, y in product(range(20), range(17)):
        print 1 + sum(int(n) for n in grid[x][y: y + 4])

您应该使用 sum 函数.当然，如果你用变量隐藏它，你就不能，所以我把它改成了 my_sum

You should be using the sum function. Of course you can't if you shadow it with a variable, so I changed it to my_sum

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