Python 3, an Illustrated Tour Transcripts
Chapter: The standard library
Lecture: Print Function
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In this video we're going to talk about the print function. One of the biggest changes for Python 3 is the print function.
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In Python 2 print was not a function, but it was a statement, it was built in into the language
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and that's changed in Python 3 just to make things a little bit more consistent. Guido wanted to change that into a function.
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Let's look at some of the features or changes that that brings. In Python 3, rather than calling print as a statement, we call it as a function
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and so you'll note that there are now parentheses when we call something as a callable in Python, we insert parentheses there.
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So we're invoking print and we're passing in one and the string one as parameters
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and note that Python prints out 1 and puts a space in there and then print another one.
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It also puts a new line at the end here that you can't really see, but it's doing that.
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Now if we change this a little bit, so one of the things that Python 3 brings about is it allows us to use keyword arguments,
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And we can use 2 keyword arguments with the print function sep and end, and sep is what goes in between the arguments that we provide
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and end is what goes in the end. The default sep is a space and the default for end is a new line.
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You'll note that I change them here and we see that I've changed the output here, it doesn't put a new line at the end.
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Here's just another slide showing that the sep comes in between the arguments and end comes at the end,
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if we have multiple arguments sep will be inserted between each one of those. And that's it, there isn't that much to it
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other than this is meant to be a thing that makes Python more consistent and to eliminate some of the statements in Python 2.
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I'll just go on a little rant here about print I personally think that you shouldn't check-in print into your code.
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If you need to print something you're probably either logging it or wanting to log it for debugging purposes.
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So you should use the logging module for that. And if you want to print something out to the screen,
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you can be slightly more explicit by calling the write method on the sys.stdout attribute found in the system module,
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that will write out to the standard out which typically writes out to the screen. I think that's a little bit more explicit and conveys your intention,
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whereas print, it's not sure whether you want something go out to the screen always or whether you just want it there for debug purposes.
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So if you sort of draw a line in the sand and say if I need to print something for debug, I'm going to use logging,
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if I need to print something out to the screen in production code or whatnot, I'll call sys.stdout.write
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Thanks for watching, I hope you learned a little bit about the print function in this video.