Create file path from variables

Question

Hello,

I am looking for some advice as to the best way to generate a file path using variables, currently my code looks similar to the following:

path = /my/root/directory
for x in list_of_vars:
        if os.path.isdir(path + '/' + x):  # line A
            print(x + ' exists.')
        else:
            os.mkdir(path + '/' + x)       # line B
            print(x + ' created.')

For lines A and B as shown above, is there a better way to create a file path as this will become longer the deeper I delve into the directory tree?

I envisage an existing built-in method to be used as follows:

create_path(path, 'in', 'here')

producing a path of the form /my/root/directory/in/here

If there is no built in function I will just write myself one.

Thank you for any input.

Answer 1

Yes there is such a built-in function: os.path.join.

>>> import os.path
>>> os.path.join('/my/root/directory', 'in', 'here')
'/my/root/directory/in/here'

Answer 2

You want the path.join() function from os.path.

>>> from os import path
>>> path.join('foo', 'bar')
'foo/bar'

This builds your path with os.sep (instead of the less portable '/') and does it more efficiently (in general) than using +.

However, this won't actually create the path. For that, you have to do something like what you do in your question. You could write something like:

start_path = '/my/root/directory'
final_path = os.join(start_path, *list_of_vars)
if not os.path.isdir(final_path):
    os.makedirs (final_path)