从数据框列中的字符串列表中返回所有子字符串[重复]答案

【问题标题】：return all substrings from a list of strings in a dataframe column [duplicate]从数据框列中的字符串列表中返回所有子字符串[重复]
【发布时间】：2019-09-15 23:14:53
【问题描述】：

我需要搜索 df 列并从列表中返回所有子字符串。

myList= ['a cat', 'the dog', 'a cow']

example df
'col A'
there was a cat with the dog
the cow was brown
the dog was sick

这会拆分列表中的单词并且只返回单个单词

df['col B'] = df['col A'].apply(lambda x: ';'.join([word for word in x.split() if word in (myList)]))

还尝试添加一个 np any...

df['col B'] = df['col A'].apply(lambda x: ';'.join(np.any(word for word in df['col A'] if word in (myList))))

需要退货

'col B'
a cat;the dog
NaN
the dog

【问题讨论】：

标签： python pandas numpy lambda

【解决方案1】：

你可以

s = df.col.str.extractall(f'({"|".join(myList)})')
res = s.groupby(s.index.get_level_values(0))[0].agg(';'.join)
df.loc[res.index, 'new'] = res

                            col            new
0  there was a cat with the dog  a cat;the dog
1             the cow was brown            NaN
2              the dog was sick        the dog

【讨论】：

【解决方案2】：

这应该可行，你已经接近了：

import numpy as np

df['col B'] = df['col A'].apply(lambda x: ';'.join([m for m in myList if m in x])).replace('',np.nan)

结果：

                          col A          col B
0  there was a cat with the dog  a cat;the dog
1             the cow was brown            NaN
2              the dog was sick        the dog

【讨论】：