Replacing values in Pandas Dataframe Column with new text and ascending number, using python

Question

Python beginner here. I have values in a Pandas Dataframe that I would like to change to a new value. Also, I then want to apply an ascending value at the end of the new text. My zone column below needs to be changed to still group by zone.

This is an example of how my Dataframe currently looks:

value	section	zone
1	red	25
2	red	25
3	grey	28
4	blue	35
5	yellow	35
6	yellow	35
7	blue	50
8	green	50

This is the changes in the 'zone' column I would like to make:

value	section	zone
1	red	Zone1
2	red	Zone1
3	grey	Zone2
4	blue	Zone3
5	yellow	Zone3
6	yellow	Zone3
7	blue	Zone4
8	green	Zone4

I'm not quite sure how to handle this problem. I'm assuming I need to use some sort of dataframe.replace(). I am not too skilled with python yet, so I hope this question makes sense.

Answer 1

Try:

df['zone'] = 'Zone' + (df.groupby('zone').ngroup() + 1).astype(str)
print(df)

Prints:

   value section   zone
0      1     red  Zone1
1      2     red  Zone1
2      3    grey  Zone2
3      4    blue  Zone3
4      5  yellow  Zone3
5      6  yellow  Zone3
6      7    blue  Zone4
7      8   green  Zone4