A script that concatenates all csv's within all subfolders

concat.py

import os
import csv

input_path = './input'
output_path = './output'

# If you don't have an .env set up, just pass a string here of what you want the first column name to be.
# Ideally it's descriptive of what the folders are organized by. For example, if the folders are all named after
# different months in a calendar year, "months" would be a good string to pass.
folder_type = os.environ["FOLDER_TYPE"]
type_name = folder_type


def parseCSV(subdir, file):
    with open(subdir + "/" + file, 'r') as input_file:
        lines = csv.reader(input_file)
        with open(output_path + "/concat.csv", 'a') as output_file:
            csvwriter = csv.writer(output_file)
            for line in lines:
                csvwriter.writerow([type_name] + line)
            output_file.flush()


for subdir, dirs, files in os.walk(input_path):
    for file in files:
        # If the subdirectory is within the input folder and not at its root,
        # replace the first column value with the folder name.
        if subdir != input_path: type_name = subdir.replace(input_path + "/", "")
        if '.csv' in file: parseCSV(subdir, file)