CODEWITHSUNDEEP
pythonpandasgroupingdataframe
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beta

Reputation: 5676

pandas groupby access last group

I have a pandas DataFrame looking like this:

date      info          
A         x
A         y 
B         z
B         x
C         y

I only want to know the last date. In this case it is C.

I thought that I can get this by grouping and sorting by the Date column:

 df.groupby('date', sort=True)

... and then accessing the last group. However, there is no way of accessing the last group as one-liner? Is there a better way to do this?

Upvotes: 2

Views: 618

Answers (2)

roman
roman

Reputation: 117370

If you just want to get the date as a value, your own answer is fine. But if you want to get the actual record with biggest date, you can use head():

In [4]: df.sort('date', ascending=False).head(1)
Out[4]: 
  date info
4    C    y

You can also use ascending parameter to sort by other columns.

In [4]: df.sort(columns=['date', 'info'], ascending=[False, True]).head(1)
Out[4]: 
  date info
4    C    y

Upvotes: 1

beta
beta

Reputation: 5676

I think I was just over-complicating things. to get C this should be enough:

df['date'].max()

Upvotes: 2

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