Python IO: disable standard output stream and print what we want

Question

Say I have a python program composed of three lines.

if __name__=“__main__”:
   foo( )
   print “Hello”

Here, foo( ) is a third-part function that outputs things to the standard output. E.g, foo( ) has only one line print 'I am here'. The point is that I have no permission to change foo() which may contain output statements, and I don't want to mix its output with mine.

Question:

How can I change the third line of the program above (print “Hello”), so that this program

1.only prints “Hello”, and

2.does not print anything from foo( )?

Thanks for your ideas.

If you want to access the value later you can store it in a StringIO object http://pastebin.com/NHWAjJQv — Padraic Cunningham, Apr 27 '15 at 19:55

EvenLisle · Accepted Answer · 2015-04-27T19:51:02.133

4

You can redirect stdout to os.devnull (the null device); the following:

import os
import sys
def foo():
  print "foo"
if __name__ == "__main__":
  out = sys.stdout
  null = open(os.devnull, 'w')
  sys.stdout = null
  foo()
  sys.stdout = out
  print "Hello"

will print Hello. You can read about the null device here.

edited Apr 27 '15 at 19:51

answered Apr 27 '15 at 19:47

EvenLisle

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Thanks so much for your quick response. I have been looking for something like >/dev/null. – zell Apr 27 '15 at 19:50
No need to thank me - rather accept my question, I don't mind the reputation ;P – EvenLisle Apr 27 '15 at 19:53

Python IO: disable standard output stream and print what we want

1 Answers1