Get first 3 letters of a string from a dataframe column-CodePudding

How to get extract first 3 letters from a string in dataframe column and store them in a new column.

Extract the first three letters/numbers from the column 'A' and store it in the column 'C'

DATA:

   A        B      
12525    1FWE23   
14654    22354    
24798    32684     
38945    45368     
46456    46485     
AD545    45346     
A5D66    58446

EXPECTED :

   A        B      C
12525    1FWE23   125       
14654    22354    146
24798    32684    247
38945    45368    389
46456    46485    464
AD545    45346    AD5
A5D66    58446    A5D

CodePudding user response：

First, we re-create the dataframe from the example you provided:

from io import StringIO

s = """
   A        B      
12525    1FWE23   
14654    22354    
24798    32684     
38945    45368     
46456    46485     
AD545    45346     
A5D66    58446      
"""

df = pd.read_csv(StringIO(s), sep="\s ", engine='python')

Next, create a new column C by using string accessor methods:

df['C'] = df['A'].str.slice(0, 3)

# Equivalently:
# df['C'] = df['A'].str[:3]

Verifying that the result is as desired via print(df):

       A       B    C
0  12525  1FWE23  125
1  14654   22354  146
2  24798   32684  247
3  38945   45368  389
4  46456   46485  464
5  AD545   45346  AD5
6  A5D66   58446  A5D