Python-使用正则表达式模式替换 DataFrame 中列表中的单词

Question

我有以下列表和数据框:

mylist = ['foo', 'bar', 'baz']
df = pd.DataFrame({'Col1': ['fooThese', 'barWords', 'baz are', 'FOO: not', 'bAr:- needed'],
                   'Col2': ['Baz:Neither', 'Foo Are', 'barThese', np.nan, 'but this is fine']})

如果在 DataFrame 中找到，我想替换 mylist 中的字符串。我可以使用以下正则表达式模式替换一些:

pat = '|'.join([r'\b{}'.format(w) for w in mylist])
df2 = df.replace(pat, '', regex=True)

但是这并没有放置所有实例。我想要的输出如下:

    Col1     Col2
0   These    Neither
1   Words    Are
2   are      These
3   not      NaN
4   needed   but this is fine

Answer 1

您必须使用 ?i 正则表达式标志，这使得您的替换不区分大小写，同时删除特殊字符:

mydict = {f'(?i){word}': '' for word in mylist}
df2 = df.replace(mydict, regex=True).replace('[:-]', '', regex=True)

      Col1              Col2
0    These           Neither
1    Words               Are
2      are             These
3      not               NaN
4   needed  but this is fine

或者您可以将特殊字符添加到字典中，这样您就不必调用 DataFrame.replace 两次:

mydict = {f'(?i){word}': '' for word in mylist}#.update({'[:-]': ''})
mydict['[:-]'] = ''
df2 = df.replace(mydict, regex=True)

      Col1              Col2
0    These           Neither
1    Words               Are
2      are             These
3      not               NaN
4   needed  but this is fine