csv concatenation

csvconcat.py

import csv

mydir = "C:/Users/Nessa/Documents/Work/Coding/Test"
os.chdir(mydir)

all_filenames = [i for i in glob.glob("*.{}".format("csv"))]

all_data = []

for f in all_filenames:
    rows = csv.reader(f)
    for row in rows:
        all_data.append[row]

outfile = "C:/Users/Nessa/Documents/Work/Coding/Test/output.csv"

with open(outfile, 'w', newline='') as f: # This should work in Python 3, as I recall it is different in Python 2
    writer = csv.writer(f)
    for row in all_data:
        writer.writerow(row)