python-3.x - python3 - 将正则表达式映射应用于列

Question

如何将正则表达式应用于数据框列？

import pandas as pd

df = pd.DataFrame({'col1': ['negative', 'positive', 'neutral', 'neutral', 'positive']})
cdict = {'n.*': -1, 'p.*': 0}
df['col2'] = df['col1'].map(cdict)

print(df.head())

当前输出为：

:        col1  col2
: 0  negative   NaN
: 1  positive   NaN
: 2   neutral   NaN
: 3   neutral   NaN
: 4  positive   NaN

但预期的结果：

:        col1  col2
: 0  negative   -1
: 1  positive   1
: 2   neutral   -1
: 3   neutral   -1
: 4  positive   1

标签： python-3.xpandasdictionaryreplace

Answer 1

而不是series.map使用series.replacewithregex=True

df['col2'] = df['col1'].replace(cdict,regex=True)