Write a 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 · 2021-10-21T16:35:40.893

69

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(...)

Updated for Python 3:

import os, os.path

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

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

edited Oct 21 '21 at 16:35

answered May 21 '14 at 21:21

Jonathon Reinhart

132,704
33
254
328

1

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
1

@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
5

Nowadays, you can avoid the error handling by passing `exists_ok=True` to `os.makedirs` – Bananach May 14 '19 at 09:59
`exist_ok` (no `s` on the end of `exist`) – sparrowt Oct 21 '21 at 10:18

score 44 · Answer 2 · edited Mar 15 '23 at 05:40

44

Using pathlib.Path (in Python 3.5 and up, to support the exist_ok parameter):

from pathlib import Path

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

edited Mar 15 '23 at 05:40

Karl Knechtel

62,466
11
102
153

answered Jul 07 '19 at 18:38

Yakir Tsuberi

1,373
1
12
16

11

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

Note you may want to specify `parents=True` to get the expected behavior of creating all directories that don't exist for the file. – Major Major Nov 09 '22 at 03:31

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

16

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

7,032
2
34
49

2

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 13 · Answer 4 · edited Jul 08 '22 at 12:03

13

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)
with (p / 'output-text.txt').open('w') as opened_file:
    opened_file.write(...)

edited Jul 08 '22 at 12:03

Neuron

5,141
5
38
59

answered Jan 21 '21 at 20:24

Hagbard

3,430
5
28
64

score 2 · Answer 5 · 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

Write a file to a directory that doesn't exist

5 Answers5

Linked