CODEWITHSUNDEEP
pythonpython-3.xpandasdataframe
Clement Attlee
Clement Attlee

Reputation: 733

pandas rows gets shifted after I try to sort

I have this dataframe whose head looks like this:

Out[8]:
        Date    Value
0   2016-06-30  481100.0
1   2016-05-31  493800.0
2   2015-12-31  514000.0
3   2015-10-31  510700.0

I want to use the Dates column as the index and then sort the rows based on order of the Dates.

When I try to sort it based on the first column with:

df.set_index('Date', inplace=True)

the head then looks like this:

            Value
Date    
2016-06-30  481100.0
2016-05-31  493800.0
2015-12-31  514000.0
2015-10-31  510700.0

Not only the dataframe is not ordered based on the dates, the headers are messed up:enter image description here

Why does this happen and how should I correct it?

Upvotes: 0

Views: 293

Answers (1)

Fabio Lamanna
Fabio Lamanna

Reputation: 21574

You should use sort_values:

In [3]: df
Out[3]: 
         Date     Value
0  2016-06-30  481100.0
1  2016-05-31  493800.0
2  2015-12-31  514000.0
3  2015-10-31  510700.0

In [4]: df = df.sort_values(by='Date')

In [5]: df
Out[5]: 
         Date     Value
3  2015-10-31  510700.0
2  2015-12-31  514000.0
1  2016-05-31  493800.0
0  2016-06-30  481100.0

EDIT: Once sorted, you can set your desired column as index of the dataframe:

In [6]: df.set_index('Date', inplace=True)

In [7]: df
Out[7]: 
               Value
Date                
2015-10-31  510700.0
2015-12-31  514000.0
2016-05-31  493800.0
2016-06-30  481100.0

Upvotes: 2

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