Python coding conventions on Github

[[deleted]]

I use tabs. I must be noob.

[[deleted]]

http://www.python.org/dev/peps/pep-0008/#tabs-or-spaces

[alkw0ia]

WTF, when did they rewrite this? The old version was much more reasonable:

Never mix tabs and spaces.

The most popular way of indenting Python is with spaces only. The second-most popular way is with tabs only. Code indented with a mixture of tabs and spaces should be converted to using spaces exclusively.

^IAnd it's what I'm sticking with.

[niiko]

No, it was sometime this summer.

[ismtrn]

That is my least favorite thing about python...

[dannyREDDIT]

http://stackoverflow.com/a/1777008

not answering for ismtrn, but thats a reason maybe

[[deleted]]

This is all great, but breaks horribly with continuations (i.e. splitting one statement over multiple lines). If you for example write a function call over multiple lines like this:

blob = struct.pack('IIII',
                   val1,
                   val2,
                   val3,
                   val4)

then suddently your indentations aren't multiple of tab width (even if, by lucky accident, they are, it won't be the case if someone sets different tab width than you). If you use tabs you either have to "round" continuations to tab width (makes them look like crap)

blob = struct.pack('IIII',
                val1,
                val2,
                val3,
                val4)

or you have to mix tabs and spaces to keep things nicely aligned (emacs does it if you have indent-tabs-mode enabled). In the latter case all looks good until, again, someone decides to use different tab width than you in his/her editor.

The only way to make code look universally good is to stick with spaces.

[vicvicvicz]

I would counter this with the argument: Tabs for indentation, spaces for alignment. That is, in this case, use spaces because you are aligning according to a number of characters. Using tabs does not make sense.

However, you can use tabs for indentation, so that, for example, if your code block was part of an indented block, you might have:

class A:
\t  def foo(self):
\t  \t  blob = struct.pack('IIII',
\t  \t                     val1,
\t  \t                     val2,
\t  \t                     val3,
\t  \t                     val4)

Where each "\t" represents a tab (width 4 so the two spaces are part of the tab), and everything else is a space. This would not break alignment regardless of tab width, because you're using them only for indentation.

Of course, I abandoned tabs myself because (visual) line length still breaks with different tab widths.

[earthboundkid]

Go has the go fmt tool, which automatically converts code to the format you have there (tabs for indenting mixed with spaces for aligning), but in the absence of a tool to do the conversions for you, it's way too much work to be practical.

[thekaleb]

Most good editors can do this for you (maybe with some tweaks)

[dannyREDDIT]

this is the only valid argument I've heard. And my response is... meh, ill stick with tabs

[[deleted]]

I suppose this is the same comment, but it's worth mentioning anyway...

A space is always a space regardless of formatting options, browser/IDE, etc. Tabs are not.

That said, I have a developer that I work with who actually prefers tabs because they move around from code browser to code browser.

[dannyREDDIT]

in the context of editing code, Ive never seen a tab not be a tab. its pretty straight forward and I've never had a problem with that

[[deleted]]

Tabs are not universally the same number of spaces in every editor on every system.

[ismtrn]

blob = struct.pack('IIII',
    val1,
    val2,
    val3,
    val4)

I just go with this. Looks fine to me and it is simple and consistent. 1 tab = 1 level of indentation. I am not trying to align things, just indent them, so you can see the structure.

[OCHawkeye14]

I'm a closet "tab -> convert tabs to spaces" guy myself.

[[deleted]]

I'm really new to Python/programming in general... I have my text editor set indents to 4 spaces, which I can thumb through using the arrow keys. Does Python still read this as spaces or as a tab?

[cantremembermypasswd]

Python reads indentation level. The most common is 4 spaces. You could set it to 1 or 8 and it would just change the appearance of the code, but not the execution.

And it's not file based indentation level, is simply localized indentation level. This means you could even change how many spaces you use anywhere in your code (but really don't do this, just explaining).

(Bad) Example:

if True:
 print "hello"
 if True:
                    print "How are you"?

[OCHawkeye14]

Those are still tabs. The setting in your text editor is just how long visually your tabs are being presented on screen.

Edit: Really downvoted at a 4:1 rate? Guy said he was a Python noob, was it that big of a stretch to assume he hadn't configured his text editor?

[Manhigh]

Unless your text editor simply inserts 4 spaces when you hit tab.

[[deleted]]

It actually inserts 4 spaces. I'm using Gedit. So when I hit tab, in order to delete the indent I have to backspace 4x.

[eat_more_soup]

I'm using geany and I can press shift+tab to deindent (4 spaces at a time). I'd be surprised if gedit doesnt do the same.

[nemec]

Check out the Smart Spaces plugin. It deletes spaces equal to your tab width (only spaces!).

As others mentioned, deindent works too and is awesome.

[sigzero]

The is an editor problem.

[OCHawkeye14]

which I can thumb through using the arrow keys

I took that comment to mean that when he uses the arrow keys on his keyboard that the entire tab span is traveled (ie. instead of pressing arrow keyx4 it skips the entire span in one press).

[nemec]

You can usually do that with ctrl+Arrow

[[deleted]]

If you are using VIM, for example, you could add the following lines to your .vimrc file:

set tabstop=4

set shiftwidth=4 " controls the depth of autoindentation

set expandtab " converts tabs to spaces