replace-stdin.py

import argparse
import csv
import sys

parser = argparse.ArgumentParser(description='Replace values on a column level in CSV')

parser.add_argument('--column', help='The column to replace in', required=True)
parser.add_argument('--search', help='The value to search for', required=True)
parser.add_argument('--replace', help='The value to replace it with', required=True)

args = parser.parse_args()

data = sys.stdin.readlines()
csv_reader = csv.reader(data)
header = next(csv_reader)
print(','.join(header))
try:
    column_index = header.index(args.column)
except ValueError as e:
    raise Exception('Column', args.column, 'not in list.')

for row in csv_reader:
    if row[column_index] == args.search:
        row[column_index] = args.replace
    print(','.join(row))

replace.py

import argparse
import csv

parser = argparse.ArgumentParser(description='Replace values on a column level in CSV')

parser.add_argument('--file', help='The file to read from', required=True)
parser.add_argument('--column', help='The column to replace in', required=True)
parser.add_argument('--search', help='The value to search for', required=True)
parser.add_argument('--replace', help='The value to replace it with', required=True)

args = parser.parse_args()

with open(args.file, 'r', encoding='utf8') as data:
    csv_reader = csv.reader(data)
    header = next(csv_reader)
    try:
        column_index = header.index(args.column)
    except ValueError as e:
        raise Exception('Column', args.column, 'not in list.')
    
    for row in csv_reader:
        if row[column_index] == args.search:
            row[column_index] = args.replace
        print(','.join(row))

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