Intercept python's `print` statement and display in GUI

Question

I have this somewhat complicated command line function in Python (lets call it myFunction()), and I am working to integrate it in a graphical interface (using PySide/Qt).

The GUI is used to help select inputs, and display outputs. However, myFunction is designed to work as a stand-alone command line function, and it occasionnaly prints out the progress.

My question is: how can I intercept these print calls and display them in the GUI? I know it would be possible to modify myFunction() to send processEvents() to the GUI, but I would then lose the ability to execute myFunction() in a terminal.

Ideally, I would like something similar to Ubuntu's graphical software updater, which has a small embeded terminal-looking widget displaying what apt-get would display were it executed in a terminal.

Answer 1

you could redirect stdout and restore after. for example:

import StringIO
import sys

# somewhere to store output
out = StringIO.StringIO()

# set stdout to our StringIO instance
sys.stdout = out

# print something (nothing will print)
print 'herp derp'

# restore stdout so we can really print (__stdout__ stores the original stdout)
sys.stdout = sys.__stdout__

# print the stored value from previous print
print out.getvalue()