Pandas: Sort Two Columns Together in a Pair

Question

I'm trying to sort two pandas dataframe columns. I understand that Python has its own built-in function:

.sort()

But I'm wondering if Pandas has this function too and if it can be done with two columns together, as a pair.

Say for example I have the following dataset:

   sum         feature        
0  5.1269        3
1  2.8481        2     
2  -1.472        1  
3  -3.212        0

I want to obtain this:

   sum         feature        
0  -3.212        0
1  -1.472        1     
2  2.8481        2  
3  5.1269        3

Basically what I am doing here, is I am sorting the column 'feature' to get it from minimum to maximum, however I want the corresponding values in 'sum' to also change.

Can someone please help me out with this? I have seen other posts around Stackoverflow on this, however I have not found a detailed answer explaining the process, or an answer for this specific question.

anky · Accepted Answer · 2019-03-06T06:43:03.983

2

Just use:

df.sort_values('feature')

For resetting index:

df=df.sort_values('feature').reset_index(drop=True)
print(df)

      sum  feature
0 -3.2120        0
1 -1.4720        1
2  2.8481        2
3  5.1269        3

edited Mar 06 '19 at 06:43

answered Mar 06 '19 at 06:41

anky

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1

Does this also sort the values in 'sum'? – saurish Mar 06 '19 at 06:42
@Saurish yes it does – anky Mar 06 '19 at 06:43
2

@Saurish If your features are unique, this is the best solution. although if you have repeating feature values with different sums, then you may use: `df.sort_values(['feature', 'sum'])`, in that order – Mohit Motwani Mar 06 '19 at 06:44
1

I Agree with @MohitMotwani :) – anky Mar 06 '19 at 06:45
1

Thanks guys; as @jezrael already pointed out that this question is a duplicate; I guess I'm awful at searching through Stackoverflow. The information helped me out a ton. Thanks :) – saurish Mar 06 '19 at 06:48

Pandas: Sort Two Columns Together in a Pair

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