Creating file loop

Question

How can I ask the user for a file name and if it already exists, ask the user if they want to overwrite it or not, and obey their request. If the file does not exist, a new file (with the selected name) should be created. From some research on both the Python website and Stack Overflow, I've come up with this code

try:
    with open(input("Please enter a suitable file name")) as file:
        print("This filename already exists")

except IOError:
    my_file = open("output.txt", "r+")

But this will not run in Python, and doesn't do everything I want it to do.

Are you concerned with race conditions of checking for file existence? — sberry
– sberry, Commented Jul 10, 2016 at 16:27
I added the ) by the as file so now it will run, but when asking for a file name it will automatically say it has been used before, even if it hasn't — Ollie
– Ollie, Commented Jul 10, 2016 at 16:37
Race conditions : there's lots of different things (overwriting files, creating files, all in a while loop, checking for previous file existence etc) so I'm just a bit stuck ! Although there are solutions to most of those issues, I'm struggling to apply and combine them for my own use — Ollie
– Ollie, Commented Jul 10, 2016 at 16:56

sxnwlfkk · Accepted Answer · 2016-07-10 19:05:28Z

1

Alternative soltution would be (however the user would need to provide a full path):

import os

def func():
    if os.path.exists(input("Enter name: ")):
        if input("File already exists. Overwrite it? (y/n) ")[0] == 'y':
            my_file = open("filename.txt", 'w+')
        else:
            func()

    else:
    my_file = open("filename.txt", 'w+')

Don't forget to close the file object when it's not needed anymore with my_file.close().

edited Jul 10, 2016 at 19:05

answered Jul 10, 2016 at 16:33

sxnwlfkk

281 silver badge5 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

Ollie Over a year ago

Hi I tried your solution in a separate python file just on its own and the following error came up Enter nametesting Traceback (most recent call last): line 6, in <module> my_file = open("filename.txt", 'r+') FileNotFoundError: [Errno 2] No such file or directory: 'filename.txt'

Ollie Over a year ago

I changed that, and now this error appears my_file = open("filename.txt", 'r+') FileNotFoundError: [Errno 2] No such file or directory: 'filename.txt'

sxnwlfkk Over a year ago

The error message still has 'r+' in it. Did you save the script before running it?

gaganso Over a year ago

Isn't os.path.isfile a better choice since OP wants to check for regular files?

Ollie Over a year ago

@sxnwlfkk I thought I had edited, but clearly hadn't. Done it again and it seems to work, but when I enter the same name, the program just accepts it

|

Pythonista · Accepted Answer · 2016-07-10 16:25:36Z

1

You can use os.path.exists to check if a file already exists are not.

if os.path.exists(file path):
    q = input("Do you want to overwrite the existing file? ")
    if q == (your accepted answer):
       #stuff
else:
    #stuff

You could do this with a try / except if you want to abide by the whole "easier to ask for forgiveness" motto, but I think this is cleaner.

answered Jul 10, 2016 at 16:25

Pythonista

11.7k2 gold badges35 silver badges52 bronze badges

5 Comments

Ollie Over a year ago

What do you put in the (file path) ?

gaganso Over a year ago

Isn't os.path.isfile a better choice since OP wants to check for regular files?

Pythonista Over a year ago

You could do this as one option file_path= input("Specify the file path")

Ollie Over a year ago

Why do they need to specify the file path?

Pythonista Over a year ago

Why do you mean why do they need to specify a file path? Your entire question centers around doing this and then checking for existence etc....

Collectives™ on Stack Overflow

Creating file loop

2 Answers 2

11 Comments

5 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

11 Comments

5 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related