extract_and_merge_csv_cols.py

#!python
"""
extract_and_merge_csv_cols.py is a script to extract a target column from a set
of csvs and merge them into a single csv where each column name is the filename
of the original csv.

Usage:
    extract_and_merge_csv_cols.py <target_col> <csvs>...
"""

import argparse

import pandas as pd


def main():
    parser = argparse.ArgumentParser(
        description="Extract a target column from a set of csvs and merge them into a single CSV."
    )
    parser.add_argument("target_col", help="The target column to extract")
    parser.add_argument("csvs", nargs="+", help="The csvs to extract from")
    args = parser.parse_args()

    dfs = []
    for csv in args.csvs:
        df = pd.read_csv(csv)
        df = df[[args.target_col]].rename(columns={args.target_col: csv})
        dfs.append(df)

    df = pd.concat(dfs, axis=1)
    df.to_csv("merged.csv", index=False)


if __name__ == "__main__":
    main()

$ cat foo.csv 
foo,bar,baz
1,2,3
4,5,6
7,8,9

$ cat bar.csv 
foo,bar,baz
7,8,9
4,5,6
1,2,3

$ ./extract_and_merge_csv_cols.py foo foo.csv bar.csv

$ cat merged.csv 
foo.csv,bar.csv
1,7
4,4
7,1