80

I would like to run a command in Python Shell to execute a file with an argument.

For example: execfile("abc.py") but how to add 2 arguments?

2
  • How is the code in the file you want to execute retrieve the arguments? Commented Apr 26, 2011 at 11:42
  • I know this is old question, but you could alternately probably pass values to run a py file in a file and just open it up and read in the values. Commented Apr 8, 2021 at 2:01

13 Answers 13

60

Actually, wouldn't we want to do this?

import sys
sys.argv = ['abc.py','arg1', 'arg2']
execfile('abc.py')
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3 Comments

...and then, it turns out, that python points to a different (2-vs-3) version of Python :)
I have to downvote buggywhip's answer because he missed this subtlety.
Even still this will fail if abc.py reads from sys import argv
59

try this:

import sys
sys.argv = ['arg1', 'arg2']
execfile('abc.py')

Note that when abc.py finishes, control will be returned to the calling program. Note too that abc.py can call quit() if indeed finished.

5 Comments

Nothing is being passed to abc.py as far as I can tell, nor can I see why it should.
When my 'abc.py' has argparse to parse input arguments, I got an error with this method: too few arguments. I ran python abc.py arg1 arg2 in terminal (this method works without an error) and then printed the content of sys.argv by printing and found that sys.argv contains the name 'abc.py' as the first element of the list. Actually, user2757262's code below with sys.argv = ['abc.py','arg1', 'arg2'] was the one that worked!
The documentation also says, "argv[0] is the script name" .
@AntiEarth: There being but one sys in a process, it will find what you put there.
@KouichiC.Nakamura I see that execfile is removed from Python3. How can I use exec with arguments?
58

execfile runs a Python file, but by loading it, not as a script. You can only pass in variable bindings, not arguments.

If you want to run a program from within Python, use subprocess.call. E.g.

import subprocess
subprocess.call(['./abc.py', arg1, arg2])

4 Comments

The following format works for me: subprocess.call("python abc.py 'arg1'", shell=True)
@geotheory Sure that works, but it's less safe and it gets hairy when you want to pass strings with quotes in them to a subprocess.
Can you explain what do you mean with "loading it, not as a script"? What's the difference?
@marco: The idea is that a “script” would be a separate process with its own command line. execfile runs in the current process, so (if it’s relevant) uses the current command line. In that sense, you can’t use it without “passing” arguments!
30
import sys
import subprocess

subprocess.call([sys.executable, 'abc.py', 'argument1', 'argument2'])

Comments

12

You're confusing loading a module into the current interpreter process and calling a Python script externally.

The former can be done by importing the file you're interested in. execfile is similar to importing but it simply evaluates the file rather than creates a module out of it. Similar to "sourcing" in a shell script.

The latter can be done using the subprocess module. You spawn off another instance of the interpreter and pass whatever parameters you want to that. This is similar to shelling out in a shell script using backticks.

Comments

12

For more interesting scenarios, you could also look at the runpy module. Since python 2.7, it has the run_path function. E.g:

import runpy
import sys

# argv[0] will be replaced by runpy
# You could also skip this if you get sys.argv populated
# via other means
sys.argv = ['', 'arg1' 'arg2']
runpy.run_path('./abc.py', run_name='__main__')

Comments

5

You can't pass command line arguments with execfile(). Look at subprocess instead.

1 Comment

See @user2757262's answer above.
2

If you set PYTHONINSPECT in the python file you want to execute

[repl.py]

import os
import sys
from time import time 
os.environ['PYTHONINSPECT'] = 'True'
t=time()
argv=sys.argv[1:len(sys.argv)]

there is no need to use execfile, and you can directly run the file with arguments as usual in the shell:

python repl.py one two 3
>>> t
1513989378.880822
>>> argv
['one', 'two', '3']

1 Comment

This goes without saying for some users, but you can use the above approach on variables that were defined/used within functions by adding those variables to the global namespace inside the function.
2

If you want to run the scripts in parallel and give them different arguments you can do like below.

import os
os.system("python script.py arg1 arg2 & python script.py arg11 arg22")

3 Comments

Please don’t recommend os.system—its legitimate use cases are very rare.
Why is it illegitimate @DavisHerring? This comment isn't helpful to future readers who may want to know why Mehmet's solution is unsuitable.
@Lou: That doesn't fit in a comment. I was surprised that I couldn't find one to link here, so I asked/answered my own.
1

Besides subprocess.call, you can also use subprocess.Popen. Like the following

subprocess.Popen(['./script', arg1, arg2])

Comments

0

This works:

subprocess.call("python abc.py arg1 arg2", shell=True)

Comments

0
runfile('abc.py', ['arg1', 'arg2'])

Comments

0

This works for me :

import subprocess
subprocess.call(['python.exe', './abc.py', arg1, arg2])

Comments

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