Rebinding stdout (was: Re: Python! Is! Truly! Amazing!)

[Simo Melenius]

Ron Garret <rNOSPAMon at flownet.com> writes:

> (with-output-to-string (s)
>   (let ( (*standard-output* s) )
>     (call-html-generating-code)
>     s))
>
> Is there an equivalent Python trick to capture a function call's output 
> as a string?

I've sometimes replaced sys.stdout (and/or sys.stderr) to
capture/redirect debugging information in existing code that has
unwisely just "print"ed error and warning messages, instead of using
sys.stderr or error logging modules.

py> def with_output_to_string (func):
...     try:
...         sys.stdout = StringIO.StringIO ()
...         func ()
...         return sys.stdout.getvalue ()
...     finally:
...         sys.stdout = sys.__stdout__
...
py> def printing_code ():
...     print "Foobar"
...
py> with_output_to_string (printing_code)
'Foobar\n'
py>


br,
S