比较列中的字符串并在python中创建相应的新列 [英] comparing string in a column and creating respective a new column in python

问题描述

我有如下所示的数据帧.我需要将数据框中的列与字符串进行比较，然后创建一个新列.

I have data frame as shown below. I need to compare column in a data frame with the string and creating a new column.

DataFrame:

DataFrame:

col_1
AB_SUMI
AK_SUMI
SB_LIMA
SB_SUMI
XY_SUMI

如果col_1中存在"AB"，"AK"，"SB"，则应使用各自的值创建一个新列，否则应在列值中添加"*".

If 'AB','AK','SB' are present in col_1 it should create a new column with their respective values otherwise '*' should come in the column value.

预期输出:

col_1      new_col
AB_SUMI     AB
AK_SUMI     AK
SB_LIMA     SB
SB_SUMI     SB
XY_SUMI     *

我尝试使用下面的代码，但是没有解决.

I have tried with below code but not worked out.

list=['AB','AK','AB']

for item in list:
    if df['col1'].str.contains(item).any():
        df['new']=item

在这方面请帮助我.预先感谢

please help me in this regard. Thanks in advance

推荐答案

您可以使用NaN http://pandas.pydata.org/pandas-docs/stable/generation/pandas.Series.fillna.html"rel =" nofollow noreferrer> fillna :

You can use extract with regex created with list by join | (or), last replace NaN by fillna:

L= ['AB','AK','SB']
a = '(' + '|'.join(L) + ')'
print (a)
(AB|AK|SB)

df['new'] = df.col_1.str.extract(a, expand=False).fillna('*')
print (df)
     col_1 new
0  AB_SUMI  AB
1  AK_SUMI  AK
2  SB_LIMA  SB
3  SB_SUMI  SB
4  XY_SUMI   *

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