Menu
PEP 8 suggests lines should be limited to 79 characters. This is because it allows you to have multiple files open next to one another, while also avoiding line wrapping. Of course, keeping statements to 79 characters or less is not always possible.
PEP 8 is a document that provides various guidelines to write the readable in Python. PEP 8 describes how the developer can write beautiful code. It was officially written in 2001 by Guido van Rossum, Barry Warsaw, and Nick Coghlan. The main aim of PEP is to enhance the readability and consistency of code.
This immediately brought to mind another character limit that many Python programmers face in their day-to-day lives: the 79-character line limit suggested by Python's PEP8 style guide: Limit all lines to a maximum of 79 characters.
Traditional line length research, limited to print-based text, gave a variety of results, but generally for printed text it is widely accepted that line lengths fall between 45 and 75 characters per line (cpl), though the ideal is 66 cpl (including letters and spaces).
Much of the value of PEP-8 is to stop people arguing about inconsequential formatting rules, and get on with writing good, consistently formatted code. Sure, no one really thinks that 79 is optimal, but there's no obvious gain in changing it to 99 or 119 or whatever your preferred line length is. I think the choices are these: follow the rule and find a worthwhile cause to battle for, or provide some data that demonstrates how readability and productivity vary with line length. The latter would be extremely interesting, and would have a good chance of changing people's minds I think.
Keeping your code human readable not just machine readable. A lot of devices still can only show 80 characters at a time. Also it makes it easier for people with larger screens to multi-task by being able to set up multiple windows to be side by side.
Readability is also one of the reasons for enforced line indentation.
I am a programmer who has to deal with a lot of code on a daily basis. Open source and what has been developed in house.
As a programmer, I find it useful to have many source files open at once, and often organise my desktop on my (widescreen) monitor so that two source files are side by side. I might be programming in both, or just reading one and programming in the other.
I find it dissatisfying and frustrating when one of those source files is >120 characters in width, because it means I can't comfortably fit a line of code on a line of screen. It upsets formatting to line wrap.
I say '120' because that's the level to which I would get annoyed at code being wider than. After that many characters, you should be splitting across lines for readability, let alone coding standards.
I write code with 80 columns in mind. This is just so that when I do leak over that boundary, it's not such a bad thing.
I believe those who study typography would tell you that 66 characters per a line is supposed to be the most readable width for length. Even so, if you need to debug a machine remotely over an ssh session, most terminals default to 80 characters, 79 just fits, trying to work with anything wider becomes a real pain in such a case. You would also be suprised by the number of developers using vim + screen as a day to day environment.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With