CODEWITHSUNDEEP
pythonpandas
YohanRoth
YohanRoth

Reputation: 3253

How to select max and min value in a row for selected columns

Let us say we have the following table enter image description here

and I want to find max and min value for every row for a set of specific columns (let's say CENSUS2010POP, ESTIMATESBASE1010, POPESTIMATE2010). How to do it with Pandas?

Upvotes: 8

Views: 10287

Answers (2)

Taie
Taie

Reputation: 1179

Suppose you have the following data df

    a   b   c
    0.2 1.2 9
    0.5 2.1 1.1
    3.9 0.2 1.9
    4.6 3.3 7.8

If you want is to find max value for each row BUT for only few columns, you could do column slicing (for example, columns a and b only) as follows :

df.assign(max_value=(df[df.columns[0:2]]).values.max(1))

The result will be:

    a        b       c    max_value
0   0.2     1.2     9.0     1.2
1   0.5     2.1     1.1     2.1
2   3.9     0.2     1.9     3.9
3   4.6     3.3     7.8     4.6

Upvotes: 0

jezrael
jezrael

Reputation: 862591

I think you need min and max:

df_subset=df.set_index('CTYNAME')[['CENSUS2010POP', 'ESTIMATESBASE1010', 'POPESTIMATE2010']]
df1 = df_subset.min(axis=1)
print (df1)

df2= df_subset.max(axis=1)
print (df2)

EDIT:

df = pd.DataFrame({'CTYNAME':['Alabama','Autauga County','Baldwin County','Barbour County'],
                   'CENSUS2010POP':[4,5,6,2],
                   'ESTIMATESBASE1010':[7,8,9,3],
                   'POPESTIMATE2010':[1,3,5,5]})

print (df)
   CENSUS2010POP         CTYNAME  ESTIMATESBASE1010  POPESTIMATE2010
0              4         Alabama                  7                1
1              5  Autauga County                  8                3
2              6  Baldwin County                  9                5
3              2  Barbour County 

df_subset=df.set_index('CTYNAME')[['CENSUS2010POP', 'ESTIMATESBASE1010', 'POPESTIMATE2010']]
df1 = df_subset.max(axis=1) - df_subset.min(axis=1)
print (df1)
CTYNAME
Alabama           6
Autauga County    5
Baldwin County    4
Barbour County    3
dtype: int64

print (df1.nlargest(1).reset_index(name='top1'))
   CTYNAME  top1
0  Alabama     6

Upvotes: 8

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