如何获取熊猫数据框列的最大值并在另一列中找到相应的值？

Question

I want to take max value of a pandas dataframe column and find the corresponding value in another column? Let's assume there are not duplicates in the maximum value, so you are always returning only one value. For example,

GPA   ID
2.3  Tina1
3.4  Bob1
3.6  Lia1
2.9  Tina2
4.0  Blake1
4.5  Conor2

Here the max GPA is 4.5, but I want to return the corresponding id for the max GPA, so I would return Conor2. I am unsure of how to do this, so help would be greatly appreciated :) Thanks!

Answer 1

You can use

df.loc[df.GPA == df.GPA.max(), 'ID']

You get

5    Conor2

If you don't want the index but just the value, try

df.loc[df.GPA == df.GPA.max(), 'ID'].values[0]

You get

'Conor2'

Answer 2

Let's use idxmax :

df.set_index('ID').idxmax()

Output:

GPA    Conor2
dtype: object

A series with a single value Conor2 .