Iteratively naming columns in a pandas DataFrame?

Question

I feel like this should be easy but I couldn't find a solution.

The current column names are just: 0,1,2,3,4,5.

And I want to rename them to: bid_1, bidsize_1, bid_2, bidsize_2, bid_3, bidsize_3.

I've tried ['bid_' + str(i) for i in range(1,4)] + ['bidsize_' + str(i) for i in range(1,4)] and got ['bid_1', 'bid_2', 'bid_3', 'bidsize_1', 'bidsize_2', 'bidsize_3'] . But the ordering is not what I wanted.

Answer 1

try this-

df.columns = [s+str(i+1) for i in range(len(df.columns)//2) for s in ['bid_', 'bidsize_']]

['bid_1',
 'bidsize_1',
 'bid_2',
 'bidsize_2',
 'bid_3',
 'bidsize_3']