[Python-ideas] Improve readability of long numeric literals

[Victor Stinner]

2016-02-09 22:40 GMT+01:00 Manuel Cerón <ceronman at gmail.com>:
> Hi everyone!
>
> Sometimes it's hard to read long numbers. For example:
>
>>>> opts.write_buffer_size = 67108864
>
> Some languages (Ruby, Perl, Swift) allow the use of underscores in numeric
> literals, which are ignored.

Yeah, I saw this (in Perl) and I think that it's a good idea.


> Another option is to use spaces instead of underscores:
>
>>>> opts.write_buffer_size = 67 108 864

It sounds error-prone to me. It's common that I forget a comma in a tuple like :

x = (1,
     2
     3)

I expect a SyntaxError, not x = (1, 23).

It can also occur on a single line:  x = (1, 2 3)

> I have seen some old discussions around this, but nothing on this list or a
> PEP. With Python being use more and more for scientific and numeric
> computation, this is a small change that will help with readability a lot.
> And, as far as I can tell, it doesn't break compatibility in any way.

I'm not sure that a PEP is required. We just have to clarify where
underscore are allowed exactly. See the discussion above they are
corner cases on float and complex numbers.

Victor