Access index in pandas.Series.apply

Question

Lets say I have a MultiIndex Series s:

>>> s
     values
a b
1 2  0.1 
3 6  0.3
4 4  0.7

and I want to apply a functi

Answer 1

You can access the whole row as argument inside the fucntion if you use DataFrame.apply() instead of Series.apply().

def f1(row):
    if row['I'] < 0.5:
        return 0
    else:
        return 1

def f2(row):
    if row['N1']==1:
        return 0
    else:
        return 1

import pandas as pd
import numpy as np
df4 = pd.DataFrame(np.random.rand(6,1), columns=list('I'))
df4['N1']=df4.apply(f1, axis=1)
df4['N2']=df4.apply(f2, axis=1)