如何在列表列表中找到最常见的元素? [英] How to find most common element in a list of list?

问题描述

我了解

a = max(set(lst), key=lst.count)

将导出列表中最常见的元素

will derive most common element in a list

但是如何在不使用辅助函数的情况下导出列表列表中最常见的元素?

but how do you derive most common element in a list of list without using helper function?

例如

lst = [['1','2','3','4'],['1','1','1','1'],['1','2','3','4']]

输出应等于1.

当我尝试a = max(set(lst), key=lst.count)

它写builtins.TypeError: unhashable type: 'list'

有人可以帮助我吗?

推荐答案

有很多方法，但是我想让您知道，标准模块中有一些不错的工具可以解决这类问题，例如 collections.Counter :

There are many ways, but I wanted to let you know that there are some nice tools for that kind of things in the standard modules, e.g. collections.Counter:

In [1]: lst = [['1','2','3','4'],['1','1','1','1'],['1','2','3','4']]
In [2]: from collections import Counter
In [3]: from operator import itemgetter
In [4]: max((Counter(l).most_common(1)[0] for l in lst), key=itemgetter(1))[0]
Out[4]: '1'

或者，您可以(有点)将当前解决方案应用于每个子列表:

Or, you could (kinda) employ your current solution for each of the sublists:

In [5]: max(((max(set(l), key=l.count), l) for l in lst),
   ...: key=lambda x: x[1].count(x[0]))[0]
Out[5]: '1'

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