高效的双循环 [英] Efficient double for loop

问题描述

执行双重for循环的最有效方法(或Python方式)如下所示(我知道如何执行此操作以进行列表理解，但不返回单个对象):

What is the most efficient (or Pythonic way) to carry out a double for loop as in below (I know how to do this for list comprehension but not for a single object to be returned):

for i in range(0, 9):
    for j in range(0, 9):
        if self.get(i)[j] == "1":
            return (i, j)

推荐答案

>>> next(((i, j)
           for i in range(0, 9)
           for j in range(0, 9)
           if self.get(i)[j] == "1"), None)

如果未找到任何内容，它将返回None.

This will return None if nothing is found.

请参阅 next 的文档a>.

第一个参数是生成器.如果提供None作为第二个参数，则需要此参数.否则，您可以跳过多余的括号.如果您不提供None，尽管它会抛出 StopIteration 例外，如果未找到任何内容.

The first parameter is a generator. You need this if you supply None as the second parameter. Otherwise you can skip the extra parentheses. If you don't supply None though it will throw a StopIteration exception if nothing is found.

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