在Python中使用Lambda [英] Using lambda in Python

问题描述

我正在尝试使用lambda对列表进行某种排序.我想做的是根据距起始位置的曼哈顿距离对坐标进行排序.我知道我的语法大部分都用完了，但是好像我缺少一些小东西，谢谢！

I am trying to use lambda do to some sorting on a list. What I wanted to do is sort the coordinates based on their manhattan distance from an inital poisition. I know I have most of the syntax down but it seems like I am missing something small, Thanks!

while (len(queue) > 0):  
    queue.sort(queue, lambda x: util.manhattanDistance(curr,x))  

推荐答案

您似乎正在尝试告诉sort()方法将lambda函数用作键进行排序.这是通过关键字参数 key:

It appears that you're trying to tell the sort() method to use your lambda function as the key for sorting. This is done with the keyword argument key:

queue.sort(queue, key = [your lambda function])

重写的行是:

queue.sort(queue, key = lambda x: util.manhattanDistance(curr,x))

误解了原始lambda函数的用途；认为它是作为比较函数使用的，因为距离函数不能为负，所以没有意义

misunderstood the purpose of the original lambda function; thought it was intended as a comparison function, which doesn't make sense since distance functions can't be negative

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