[Python-ideas] Improve readability of long numeric literals

[Georg Brandl]

On 02/09/2016 10:40 PM, Manuel Cerón wrote:
> 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. They are typically used as thousands separators.
> The example above would look like this:
> 
>>>> opts.write_buffer_size = 67_108_864
> 
> Which helps to quickly identify that this is around 67 million.

> Thoughts?

I like it, and for everybody to try it out, I posted a draft patch here:

http://bugs.python.org/issue26331

Underscores are allowed anywhere in numeric literals, except:

* at the beginning of a literal (obviously)
* at the end of a literal
* directly after a dot (since the underscore could start an attribute name)
* directly after a sign in exponents (for consistency with leading signs)
* in the middle of the "0x", "0o" or "0b" base specifiers

Reviewers welcome!

cheers,
Georg