python - 从列表中搜索部分字符串并添加具有该部分字符串的列

Question

我不会在 df.column 中搜索我保存在系列中的部分字符串，也不会用我在每一行中找到的字符串创建一个新列。我的问题的一部分被解决了 pandas: test if string contains one of the substrings in a list :

For example, say I have the series s = pd.Series(['cat','hat','dog','fog','pet']), and I want to find all places where s contains any of ['og', 'at'], I would want to get everything but pet.

解决方法是:

>>> searchfor = ['og', 'at']
>>> s[s.str.contains('|'.join(searchfor))]
0    cat
1    hat
2    dog
3    fog
dtype: object

但我想得到

         pet    contains
    0    cat    at
    1    hat    at
    2    dog    og
    3    fog    og
    dtype: object

Answer 1

使用extract如果没有匹配得到 NaN，那么添加 dropna :

searchfor = ['og', 'at']
df['new'] = df['pet'].str.extract('(' + '|'.join(searchfor) + ')', expand=False)
df = df.dropna(subset=['new'])
print (df)
   pet contains1 new
0  cat        at  at
1  hat        at  at
2  dog        og  og
3  fog        og  og