Alternate Printing in Python

February 8, 2011 at 4:21 pm

I’m always forgetting how to write to the stdout in Python without the newlines at the end. Why is this useful? Progress indicators, counters, specifically sending data with a \r return feed but not a \n newline.

Python has a build in language construct called print. As mentioned there are many different things you can do with this, including advanced formatting and string replacements. All well and good unless you want more control over how things are actually getting sent out. For that you need to go directly to sys.stdout. You can create a writer with the following:

import sys
writer = sys.stdout.write
for i in range(0, 1000):
writer("\r Doing " + str(i))

This will rotate through numbers while staying on the same line. Tagged: python, tidbits, writing

You can also do:

>>> print "blah", "blah",
blah blah

The trailing comma prevents newlines. The output is blah blah.

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February 2011

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