Write file to a directory that doesn't exist

Question

How do I using with open() as f: ... to write the file in a directory that doesn't exist.

For example:

with open('/Users/bill/output/output-text.txt', 'w') as file_to_write:
    file_to_write.write("{}\n".format(result))

Let's say the /Users/bill/output/ directory doesn't exist. If the directory doesn't exist just create the directory and write the file there.

I've been using [this snippet](http://code.activestate.com/recipes/82465-a-friendly-mkdir/) for years and years. — dabhaid, May 21 '14 at 21:37

Jonathon Reinhart · Accepted Answer · 2017-12-24T16:34:53.243

47

You need to first create the directory.

The mkdir -p implementation from this answer will do just what you want. mkdir -p will create any parent directories as required, and silently do nothing if it already exists.

Here I've implemented a safe_open_w() method which calls mkdir_p on the directory part of the path, before opening the file for writing:

import os, os.path
import errno

# Taken from https://stackoverflow.com/a/600612/119527
def mkdir_p(path):
    try:
        os.makedirs(path)
    except OSError as exc: # Python >2.5
        if exc.errno == errno.EEXIST and os.path.isdir(path):
            pass
        else: raise

def safe_open_w(path):
    ''' Open "path" for writing, creating any parent directories as needed.
    '''
    mkdir_p(os.path.dirname(path))
    return open(path, 'w')

with safe_open_w('/Users/bill/output/output-text.txt') as f:
    f.write(...)

edited Dec 24 '17 at 16:34

answered May 21 '14 at 21:21

Jonathon Reinhart

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This is a great answer. Just for clarification, the `mkdir_p` function used in your code has to be defined as well, using the link provided. It does not come with Python. – huu May 21 '14 at 21:27
@HuuNguyen Added that clarification, thanks. Still not sure why someone downvoted this. – Jonathon Reinhart May 21 '14 at 21:28
For `exc.errno == errno.EEXIST` I got the error: `NameError: global name 'errno' is not defined`. Changing it to `exc.errno == 17` worked. – Jacob Beauchamp Dec 23 '17 at 21:20
@Jacob You need to `import errno`. – Jonathon Reinhart Dec 24 '17 at 16:33
4

Nowadays, you can avoid the error handling by passing `exists_ok=True` to `os.makedirs` – Bananach May 14 '19 at 09:59

score 18 · Answer 2 · edited May 12 '21 at 10:04

18

For Python 3 can use with pathlib.Path:

from pathlib import Path

p = Path('Users'/'bill'/'output')
p.mkdir(exist_ok=True)
(p / 'output-text.txt').open('w').write(...)

edited May 12 '21 at 10:04

BLimitless

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answered Jul 07 '19 at 18:38

Yakir Tsuberi

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12

4

This should be the accepted answer in 2020. There is no need to mess with custom functions and the os module anymore. – Jeff Wright Aug 09 '20 at 15:46
1

Couldn't get this working at all in W10 (using `WindowsPath`)... – mike rodent Oct 24 '20 at 13:49
2

there's a syntax error here. it should be `Path('Users/bill/output')` or `Path('Users') / 'bill' / 'output'` – ZeitPolizei Jan 26 '21 at 13:04
[You still need to close the file, even with `pathlib`.](https://stackoverflow.com/questions/61405654/recommended-way-of-closing-files-using-pathlib-module) – Leponzo Feb 01 '21 at 20:40

huu · Answer 3 · 2014-05-21T21:28:06.857

15

Make liberal use of the os module:

import os

if not os.path.isdir('/Users/bill/output'):
    os.mkdir('/Users/bill/output')

with open('/Users/bill/output/output-text.txt', 'w') as file_to_write:
    file_to_write.write("{}\n".format(result))

edited May 21 '14 at 21:28

answered May 21 '14 at 21:21

huu

5,894
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1

This doesn't handle making the intermediate directories as well. – Jonathon Reinhart May 21 '14 at 21:21
1

Of course not, and this is a complete assumption on my part. I think `/Users/bill` exists though. – huu May 21 '14 at 21:22

score 2 · Answer 4 · edited May 23 '17 at 12:32

You can just create the path you want to create the file using os.makedirs:

import os
import errno

def make_dir(path):
    try:
        os.makedirs(path, exist_ok=True)  # Python>3.2
    except TypeError:
        try:
            os.makedirs(path)
        except OSError as exc: # Python >2.5
            if exc.errno == errno.EEXIST and os.path.isdir(path):
                pass
            else: raise

Source: this SO solution

score 0 · Answer 5 · answered Jan 21 '21 at 20:24

The answer given by Yakir Tsuberi is great but I would like to add that you need the parameter "parents=True" for nested folders as explained here. Thus, the code would look as follows:

from pathlib import Path

p = Path('Users' / 'bill' / 'output')
p.mkdir(parents=True,exist_ok=True)
(p / 'output-text.txt').open('w').write(...)

Write file to a directory that doesn't exist

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