在列表列表中进行Python搜索 [英] Python search in lists of lists

问题描述

我有一个包含两个项目的列表，需要在其中进行搜索.

I have a list of two-item lists and need to search for things in it.

如果列表为:

list =[ ['a','b'], ['a','c'], ['b','d'] ]

我可以轻松地搜索一对

['a','b'] in list

现在，有没有办法查看我是否有一对仅在第二个位置存在一个字符串?我可以这样做:

Now, is there a way to see if I have a pair in which a string is present in just the second position? I can do this:

for i in range (0, len(list)):
    if list[i][1]==search:
       found=1

但是没有for循环，有没有(更好的)方法呢?我不需要知道i或在找到它之后就让循环继续进行.

But is there a (better) way without the for loop? I don't need to know i or keep the loop going after it's found.

推荐答案

您总是会有一个循环-有人可能会带一个聪明的单线，将循环隐藏在对map()或类似内容的调用中，但总会在那里.

You're always going to have a loop - someone might come along with a clever one-liner that hides the loop within a call to map() or similar, but it's always going to be there.

除非性能是主要因素，否则我总是倾向于使用简洁简洁的代码.

My preference would always be to have clean and simple code, unless performance is a major factor.

这里可能是代码的Python版本:

Here's perhaps a more Pythonic version of your code:

data = [['a','b'], ['a','c'], ['b','d']]
search = 'c'
for sublist in data:
    if sublist[1] == search:
        print "Found it!", sublist
        break
# Prints: Found it! ['a', 'c']

一旦找到匹配项，它就会跳出循环.

It breaks out of the loop as soon as it finds a match.

(顺便说一下，您在['b''d']中有一个错字.)

(You have a typo, by the way, in ['b''d'].)

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