How to delete columns containing all zeros from a csv file in python?

Question

I want to delete the columns from a csv file that contain all zeros for example like the column f, g, h, k, l. The csv file in question is populated with the script so it is not possible to hardcode the columns. I would be really grateful if you could help with it.

File.csv
a,b,c,d,e,f,g,h,i,j,k,l
1,5,4,4,5,0,0,0,6,3,0,0
2,5,3,4,1,0,0,0,7,1,0,0
1,2,6,4,1,0,0,0,9,2,0,0
5,7,3,4,2,0,0,0,2,2,0,0
7,2,9,4,3,0,0,0,1,1,0,0

Resultant expected

File.csv
a,b,c,d,e,i,j
1,5,4,4,5,6,3
2,5,3,4,1,7,1
1,2,6,4,1,9,2
5,7,3,4,2,2,2
7,2,9,4,3,1,1

Answer 1

The following approach could be used with the csv library:

1. Read the header in
2. Read the rows in
3. Transpose the list of rows into a list of columns (using zip )
4. Use a set to drop all columns that only contain 0
5. Write out the new header
6. Write out the transposed list of columns as a list of rows.

For example:

import csv
    
with open('file.csv', newline='') as f_input:
    csv_input = csv.reader(f_input)
    header = next(csv_input)   # read header
    columns = zip(*list(csv_input))   # read rows and transpose to columns
    data = [(h, c) for h, c in zip(header, columns) if set(c) != set('0')]
    
with open('file2.csv', 'w', newline='') as f_output:
    csv_output = csv.writer(f_output)
    csv_output.writerow(h for h, c in data)   # write the new header
    csv_output.writerows(zip(*[c for h, c in data]))