How do I print to console when output is redirected to a file?

Question

I want to write results of some calculations to a file with print and print some other data like progress indication to Windows console so I can see it immediately.

What I write to console is: C:\Users\BoltKey>python program.py < in.txt > out.txt.

Is there a way to overload output redirection and print to console? Or is it just wrong and I should use file functions if I want to print to the console and into files at the same time?

Here is pseudocode:

for i in range(100): for j in range(100): result = getResult(i, j) print result // print to output file consolePrint "progress: " + str(i) + "%" // print to console

Community · Accepted Answer · 2017-05-23 12:07:23Z

You can print to stderr to achieve this (your command line is only redirecting stdout to a file). There are a couple of ways to achieve this, but a good one is found in this SO answer:

 import sys from __future__ import print_function

...

 print("Message", file=sys.stderr)

Community · Accepted Answer · 2017-05-23 10:27:14Z

1

Sounds an ugly hack to me.

Just use stderr for displaying progress messages.

edited May 23, 2017 at 10:27

CommunityBot

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answered Dec 10, 2015 at 0:57

Karoly Horvath

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1 Comment

leewz Over a year ago

Should add in an example rather than requiring a click.

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