How do I add filenames to a list?

Question

I created a series of *.txt file using the for loop. But now I want to write the file names in a list. But only the last file name is getting printed in the list and the before ones gets deleted.


for i in range(3):
    i += 0
    new_file = str(i) + ".txt"
    file_list = []        
    file_list.append(new_file)

    with open(new_file, "w") as outfile:
        print("File created...")
print(file_list)

The output I am getting is ['2.txt']
I need the output to be ['0.txt', '1.txt', '2.txt']

Your declaring your list in the loop. This will delete the list every loop. Also, your incrementer is not doing anything — Joe, Sep 12 '19 at 17:53
Possible duplicate of [Python For Loop Appending Only Last Value to List](https://stackoverflow.com/questions/53784325/python-for-loop-appending-only-last-value-to-list) — Fynn Becker, Sep 12 '19 at 18:29

score 2 · Answer 1 · answered Sep 12 '19 at 17:53

You are re-initializing the file_list in each iteration of the loop. Move that part outside like so:

file_list = []        
for i in range(3):
    i += 0
    new_file = str(i) + ".txt"
    file_list.append(new_file)

    with open(new_file, "w") as outfile:
        print("File created...")
print(file_list)

score 1 · Accepted Answer · answered Sep 12 '19 at 17:54

You are recreating your list at each iteration. You should define your list before the loop:

file_list = []  
for i in range(3):
    i += 0
    new_file = str(i) + ".txt"      
    file_list.append(new_file)

    with open(new_file, "w") as outfile:
        print("File created...")
print(file_list)

score 0 · Answer 3 · answered Sep 12 '19 at 17:55

In the fourth line of your code, you're setting file_list equal to an empty list. Since this is in your loop, it's happening every time that the loop iterates! If you declare the file_list variable and set it to your starting empty list before your for loop, you should get your expected result.

How do I add filenames to a list?

3 Answers3