python - 如何为所选列选择一行中的最大值和最小值

Question

假设我们有下表

我想找到一组特定列的每一行的最大值和最小值(假设 CENSUS2010POP、ESTIMATESBASE1010、POPESTIMATE2010)。如何用 Pandas 做到这一点？

Answer 1

我想你需要min和 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)

编辑:

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