Combine columns from several CSV files into a single file and making multiple CSV file with for loop

Question

I have 14 CSV files and each has 100 columns, what i want to do is to extract first column from each file and copy it in a single csv file. I have to do it for each 100 columns (for example next step is to put second column from each file in a csv file).

What i've tried before is the code below which is perfect for extracting one column, but i want to put it in a loop so i get the 100 files at once how can i do it?

import csv
import itertools as IT

filenames = ['Sul-v1.csv', 'Sul-v2.csv','Sul-v3.csv', 'Sul-v4.csv', 'Sul-v5.csv', 'Sul-v6.csv', 'Sul-v7.csv', 'Sul-v8.csv', 'Sul-v9.csv', 'Sul-v10.csv', 'Sul-v11.csv', 'Sul-v12.csv', 'Sul-v13.csv', 'Sul-v14.csv']
handles = [open(filename, 'rb') for filename in filenames]    
readers = [csv.reader(f, delimiter=',') for f in handles]

with  open('combined.csv', 'wb') as h:
    writer = csv.writer(h, delimiter=',', lineterminator='\n', )
    for rows in IT.izip_longest(*readers, fillvalue=['']*2):
        combined_row = []
        for row in rows:
            row = row[:1] # select the columns you want
            if len(row) == 1:
                combined_row.extend(row)
            else:
                combined.extend(['']*2)
        writer.writerow(combined_row)

for f in handles:
    f.close()

Thanks in advance!

Answer 1

Use pandas.

Start by loading all csv files into one dateframe. (see here )

Next, save each column into a new csv by looping over the columns and using to_csv .

Make sure you pass the column to 'to_csv' using the ' columns ' argument