I have a batch file that runs a python script. I am running Python 3.2. I want to send a variable like an integer or string from the python script back to the batch file, is this possible?
I know I can accept command line arguments in the Python script with sys.argv. Was hoping there was some feature that allows me to do the reverse.
In your Python script, just write to standard out: sys.stdout.write(...)
I'm not sure what scripting language you are using, maybe you could elaborate on that, for now I'll assume you are using bash (unix shell). So, In your batch script you can have the output of the python script into a variable like this:
#run the script and store the output into $val
val = `python your_python_script.py`
#print $val
echo $val
EDIT it turns out, it is Windows batch
python your_python_script.py > tmpFile
set /p myvar= < tmpFile
del tmpFile
echo %myvar%
If a int is enough for you, then you can use
sys.exit(value)
in your python script. That exits the application with a status code of value
In your batch file you can then read it as the %errorlevel% environment variable.
You can't "send" a string. You can print it out and have the calling process capture it, but you can only directly return numbers from 0 through 255.
sys.exit().Ignacio is dead on. The only thing you can return is your exit status. What I've done previously is have the python script (or EXE in my case) output the next batch file to be run, then you can put in whatever values you'd like and run it. The batch file that calls the python script then calls the batch file you create.
You can try this batch script for this issue, as an example:
@echo off
REM %1 - This is the parameter we pass with the desired return code for the Python script that will be captured by the ErrorLevel env. variable.
REM A value of 0 is the default exit code, meaning it has all gone well. A value greater than 0 implies an error
REM and this value can be captured and used for any error control logic and handling within the script
set ERRORLEVEL=
set RETURN_CODE=%1
echo (Before Python script run) ERRORLEVEL VALUE IS: [ %ERRORLEVEL% ]
echo.
call python -c "import sys; exit_code = %RETURN_CODE%; print('(Inside python script now) Setting up exit code to ' + str(exit_code)); sys.exit(exit_code)"
echo.
echo (After Python script run) ERRORLEVEL VALUE IS: [ %ERRORLEVEL% ]
echo.
And when you run it a couple of times with different return code values you can see the expected behaviour:
PS C:\Scripts\ScriptTests> & '\TestPythonReturnCodes.cmd' 5
(Before Python script run) ERRORLEVEL VALUE IS: [ 0 ]
(Inside python script now) Setting up exit code to 5
(After Python script run) ERRORLEVEL VALUE IS: [ 5 ]
PS C:\Scripts\ScriptTests> & '\TestPythonReturnCodes.cmd' 3
(Before Python script run) ERRORLEVEL VALUE IS: [ 0 ]
(Inside python script now) Setting up exit code to 3
(After Python script run) ERRORLEVEL VALUE IS: [ 3 ]
PS C:\Scripts\ScriptTests
%errorlevel%