Sort pandas dataframe by column specifying custom order

Question

I got a csv that looks something like this:

col1, col2, col3, col4
txt,txt,error,txt
txt,txt,new,txt
txt,txt,new,txt
txt,txt,error,txt
txt,txt,new,txt
txt,txt,fix,txt

Id like to change the order of the rows to this

col1, col2, col3, col4
txt,txt,new,txt
txt,txt,new,txt
txt,txt,new,txt
txt,txt,fix,txt
txt,txt,error,txt
txt,txt,error,txt

so the rows follows news -> change -> error in col3

So far tried different things with:

import pandas as pd
csv_dataframe = pd.read_csv(user_submitted_csv_file)
csv_dataframe = csv_dataframe.sort_values(by=['col3'])

But its not enough since it is not alphabetical nor ascending/descending. also tried things like exstracting the rows -> deleting all rows -> adding back in correct order, but running into problems with that too...

Ric S · Accepted Answer · 2021-07-06 10:58:41Z

4

From pandas>=1.1.0 you can use the key argument of the .sort_values method to write a lambda function which defines the custom order you prefer.

To do it, you just need to define a custom dictionary with your desired order

custom_dict = {'new': 0, 'fix': 1, 'error': 2}
df.sort_values(by=['col3'], key=lambda x: x.map(custom_dict))

answered Jul 6, 2021 at 10:58

Ric S

9,3184 gold badges30 silver badges57 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

wisbucky Over a year ago

This answer is amazing. So much easier than using Categoricals. And it works on Index as well. And it can also ignore any values not in custom_dict.

Collectives™ on Stack Overflow

Sort pandas dataframe by column specifying custom order

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related