Python Pandas: Comparing two columns and returning string value if first column include character in-CodePudding

I have 2 columns first with string including X or F and second is empty. If there is any X in column 1 I want to assign 'YES' to second column if there is no X assign 'NO' Every time I run my code it is assigning value 'YES' to all of them

This example how it should look like:

My code:

for row in df['Column2']:
    if df['Column1'].str.contains('X').any():
        df['Column2'] = 'YES'
    else:
        df['Column2'] = 'NO'

CodePudding user response：

You are executing vectorized operation each time through the loop. Every time through the loop you are assigning 'YES' to the entire Column2.

Using numpy you could do:

import numpy as np

df['Column2'] = np.where(df['Column1'].str.contains('X'), 'YES', 'NO')
print(df)

Result

             Column1 Column2
0  ....X.X.X.X..X.X.     YES
1  ....X.X.X.X..X.X.     YES
2  ....X.X.X.X..X.X.     YES
3  ....X.X.X.X..X.X.     YES
4          ....F.F.F‬      NO
5          ....F.F.F      NO
6          ....F.F.F      NO
7          ....F.F.F      NO

CodePudding user response：

you can use regex to find 'X'

if df['Column1'].str.find(r'X')>1:

you can even avoid the loop as follows

(df['Column1'].str.find(r'X')>1).map({True: 'Yes', False: 'No'})