Selecting different columns in a pandas dataframe

Question

I am trying to select different columns in a pandas dataframe using selection key

Let us say my dataframe is,

import pandas as pnd
s1 = pnd.Series ([0,3,6,7])
s2 = pnd.Series ([1,4,8,9])
s3 = pnd.Series ([2,5,10,11])
df = pnd.DataFrame({'A':s1, 'B':s2, 'C':s3})

   A  B   C
0  0  1   2
1  3  4   5
2  6  8  10
3  7  9  11

and my selection key is,

s4 = pnd.Series (['A','B','C','A'])


0    A
1    B
2    C
3    A

My desired result is,

0  0
1  4
2  10
3  7

I guess I could run a for loop to do this

l = []
for idx in df.index:
    l.append( df[s4[idx]][idx])
s5 = pnd.Series(l)
print s5

Is there a better/shorter/more efficient way?

Answer 1

pnd.Series(df.lookup(df.index, s4), df.index)