Find maximum value of a column and return the corresponding row values using Pandas
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Chapters
00:00 Question
00:35 Accepted answer (Score 233)
01:27 Answer 2 (Score 115)
01:41 Answer 3 (Score 19)
02:06 Answer 4 (Score 13)
02:35 Thank you
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Full question
https://stackoverflow.com/questions/1574...
Accepted answer links:
[idxmax]: https://pandas.pydata.org/pandas-docs/st...
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Tags
#python #pandas #dataframe #max
#avk47
ACCEPTED ANSWER
Score 243
Assuming df has a unique index, this gives the row with the maximum value:
In [34]: df.loc[df['Value'].idxmax()]
Out[34]:
Country US
Place Kansas
Value 894
Name: 7
Note that idxmax returns index labels. So if the DataFrame has duplicates in the index, the label may not uniquely identify the row, so df.loc may return more than one row.
Therefore, if df does not have a unique index, you must make the index unique before proceeding as above. Depending on the DataFrame, sometimes you can use stack or set_index to make the index unique. Or, you can simply reset the index (so the rows become renumbered, starting at 0):
df = df.reset_index()
ANSWER 2
Score 124
df[df['Value']==df['Value'].max()]
This will return the entire row with max value
ANSWER 3
Score 13
The country and place is the index of the series, if you don't need the index, you can set as_index=False:
df.groupby(['country','place'], as_index=False)['value'].max()
Edit:
It seems that you want the place with max value for every country, following code will do what you want:
df.groupby("country").apply(lambda df:df.irow(df.value.argmax()))
ANSWER 4
Score 9
Use the index attribute of DataFrame. Note that I don't type all the rows in the example.
In [14]: df = data.groupby(['Country','Place'])['Value'].max()
In [15]: df.index
Out[15]:
MultiIndex
[Spain Manchester, UK London , US Mchigan , NewYork ]
In [16]: df.index[0]
Out[16]: ('Spain', 'Manchester')
In [17]: df.index[1]
Out[17]: ('UK', 'London')
You can also get the value by that index:
In [21]: for index in df.index:
print index, df[index]
....:
('Spain', 'Manchester') 512
('UK', 'London') 778
('US', 'Mchigan') 854
('US', 'NewYork') 562
Edit
Sorry for misunderstanding what you want, try followings:
In [52]: s=data.max()
In [53]: print '%s, %s, %s' % (s['Country'], s['Place'], s['Value'])
US, NewYork, 854