在Windows上使用子进程运行R脚本，似乎缺少子进程

Question

I am using python on windows. I want to call an R script in my python code.

My script R is :

c <- 3
print(paste("hello", c))

My python code calls the Rscript like this:

import subprocess
subprocess.call(['Rscript', "sb.R"])

Unfortunately I have this error message :

File "C:\Users\[...]\Local\Programs\Python\Python35-32\lib\subproce
ss.py", line 557, in call
    with Popen(*popenargs, **kwargs) as p:
  File "C:\Users\[...]\Local\Programs\Python\Python35-32\lib\subproce
ss.py", line 947, in __init__
    restore_signals, start_new_session)
  File "C:\Users\[...]\Local\Programs\Python\Python35-32\lib\subproce
ss.py", line 1224, in _execute_child
    startupinfo)
FileNotFoundError: [WinError 2] The file is not found

I have checked the following:

1) under powershell, when I enter Rscript .\\sb.R it works.

2) in the python code I tried

theproc = subprocess.Popen([sys.executable, "sbpy.py"])
theproc.communicate()

where sbpy.py contains print("hello py") . This works as well. So I assume that the library subprocess do work.

3) I tried the following code :

cmd = ['Rscript', 'sb.R']
x = subprocess.check_output(cmd, shell=True)

I have then the following error :

...
  File "C:\Users\[...]\Local\Programs\Python\Python35-32\lib\subproce
ss.py", line 708, in run
    output=stdout, stderr=stderr)
subprocess.CalledProcessError: Command '['Rscript', 'sb.R']' returned non-zero e
xit status 1

4) As for the path, I have checked and yes R folder is in my path.

I newly installed python35 on my windows machine, is it a file missing in the lib subprocess, or is it something I have missed?

Answer 1

Check your python script and Rscript in are the same file location.

Example: Create a file named sb.R and subprocess_demo.py under Desktop location. Change directory to Desktop in command prompt and run following command python subprocess_demo.py

sb.R

c <- 3
print(paste("hello", c))

subprocess_demo.py

import subprocess
subprocess.call(['Rscript', "sb.R"])