python pass variable through os.system

Question

This gets the latest mp3 file in my Directory

new_file = [(os.path.getmtime(ft) , os.path.basename(ft))
            for ft in os.listdir(path) if ft.lower().endswith('.mp3')]

new_file.sort()

Assigning the latest file to the file I am going to play

playFile = new_file[0][1]

Getting the Directory for the file.

PlayfileDir = os.getcwd() + '\\' + str(playFile)

Playing the file. This is where I get the error 'PlayfileDir' cannot be found.

os.system('start "PlayfileDir"')

Save yourself some trouble and use [`subprocess.run()`](https://docs.python.org/3/library/subprocess.html#subprocess.run). — Ilja Everilä, Dec 29 '17 at 14:44
Your file path is wrong. The file is located in `path`, not in `os.getcwd()`. — Aran-Fey, Dec 29 '17 at 14:47
But there are many things wrong here. In all the other calls, to build up the command using string concatenation. Why don't you do that in the last one as well? — Daniel Roseman, Dec 29 '17 at 14:52
Don't you means `os.system('start \'{}\''.format(PlayfileDir))`? And btw - please - don't use camelcase, snakecase ftw! — Arount, Dec 29 '17 at 14:56
@Arount: this being Windoze, those single quotes around the directory name should be double quotes. — cdarke, Dec 29 '17 at 15:13

Joe Iddon · Answer 1 · 2017-12-29T15:09:02.370

1

Since PlayfileDir is a variable that is a string, you can just concatenate it to 'start' (as pointed out by @cdarke, you need to also add the quotes!). As you have it at the moment, you are trying to start the actual string 'PlayfileDir', not the string in the variable.

So, you should do something like:

os.system('start "' + PlayfileDir + '"')

edited Dec 29 '17 at 15:09

answered Dec 29 '17 at 14:59

Joe Iddon

20,101
7
33
54

1

Note that the `PlayfileDir` variable already has a string. No need for the cast. – Code-Apprentice Dec 29 '17 at 15:01
@Code-Apprentice Yep – Joe Iddon Dec 29 '17 at 15:06
@cdarke Thanks! Am on Linux, so couldn't test this but definitely key! – Joe Iddon Dec 29 '17 at 15:09
@JoeIddon: would apply to Linux as well, although no one in their right mind would have a directory name which includes whitespace :-) – cdarke Dec 29 '17 at 15:15

score 0 · Answer 2 · answered Dec 29 '17 at 17:49

0

This is a great opportunity to start using pathlib!

from pathlib import Path

p = input("Gimme a path: ")

newest_mp3 = sorted(Path(p).glob('*.mp3'), reverse=True, key=lambda p: p.stat().st_mtime)[0]

os.system('start "{}"'.format(newest_mp3))

answered Dec 29 '17 at 17:49

aghast

14,785
3
24
56

Hi this works well but it opens a command window in which i have to type the file name to play it. Is there a way to do this automatically – Luca Jeevanjee Dec 30 '17 at 13:10
Instead of doing `os.system(...)`, do a `print(...)` and see what is being generated. – aghast Dec 30 '17 at 17:29

python pass variable through os.system

2 Answers2