I want to automatically rename the column names of a dataframe in pandas using two loops. The indices name should include "C" + "a number between 1 and m" + "a number between 1 and n".
For example, I want to rename 12 columns of a dataframe to C11, C12, C13, C14, C21, C22, C23, C24, C31, C32, C33, and C34.
For that reason I used the following code:
m = 3
n= 4
df.columns=["C"+str(i) for i in range(1, m)+ str(j) for j in range(1, n)]
But I get the following error
NameError: name ‘j’ is not defined
This code works for only one loop but not two loops. How I can fix this?
>Solution :
You can use a nested for loop that in range that will give the desired results
m = 3
n= 4
lst = [f"C{num}{num2}" for num in range(1, m + 1) for num2 in range(1, n + 1)]
You use a +1 in the for loop because range is non-inclusive