compare values in two columns of data frame

Question

I have the following two columns in pandas data frame

     256   Z
0     2    2
1     2    3
2     4    4
3     4    9

There are around 1594 rows. '256' and 'Z' are column headers whereas 0,1,2,3,4 are row numbers (1st column above). I want to print row numbers where value in Column '256' is not equal to values in column 'Z'. Thus output in the above case will be 1, 3. How can this comparison be made in pandas? I will be very grateful for help. Thanks.

Answer 1

Create the data frame:

import pandas as pd
df = pd.DataFrame({"256":[2,2,4,4], "Z": [2,3,4,9]})

ouput:

    256 Z
0   2   2
1   2   3
2   4   4
3   4   9

After subsetting your data frame, use the index to get the id of rows in the subset:

row_ids = df[df["256"] != df.Z].index

gives

Int64Index([1, 3], dtype='int64')