根据其他列创建新列，但要剥离

Question

I have a pandas DataFrame with an id column looking like this:

id                
A2015        
B2016         
C2017         

I want two new columns as follows:

id         year       name  
A2015      2015       A Q
B2016      2016       B Q
C2017      2017       C Q

so the year column should take the four last characters of the id column and the name column should take all but the last four characters and add Q .

How can this be achieved?

Answer 1

You could get these using string methods.

Get year by taking part of id string

In [60]: df['year'] = df['id'].str[1:]

And, get name by taking last four characters of id string and adding ' q'

In [61]: df['name'] = df['id'].str[:-4] + ' Q'

In [62]: df
Out[62]:
      id  year name
0  A2015  2015  A Q
1  B2016  2016  B Q
2  C2017  2017  C Q

Answer 2

    df['year'] = df['id'].apply(lambda v : v[1:])
    df['name'] = df['id'].apply(lambda v : v[0] + ' Q')

lambda functions are generally faster