将某些子字符串从一列复制到另一列？

Question

我有一列多行文字。例如：

“星期六早上真好”
“昨天是星期五”
“他晚上去商店了”

如何从每行中提取某些关键字，例如星期几（“星期一”，“星期二”，“星期三”等）并将其存储在新列中。我宁愿不循环。也许使用lambda函数？

Answer 1

不需要lambda，这里是findall

#l=['Monday',...'Sunday'] define you own list
df['Newcol']=df.Date.str.findall('|'.join(l))
0    [Saturday]
1      [Friday]
2            []
Name: Date, dtype: object

Answer 2

您可以为此使用pandas.Series.str.extract：

words = ['Saturday', 'Friday']
df['Word'] = df['Strings'].str.extract(r'({})'.format('|'.join(words)))

print(df)

                         Strings      Word
0      Saturday morning was nice  Saturday
1           Yesterday was Friday    Friday
2  He went to the store at night       NaN