[Python-ideas] 1_000_000

[MRAB]

On 06/05/2011 23:51, Cameron Simpson wrote:
> On 06May2011 15:40, Ethan Furman<ethan at stoneleaf.us>  wrote:
> | Bruce Leban wrote:
> |>Is _ just ignored in numbers or are there more complex rules?
> |>
> |>     * 1_2345_6789  (can I use groups of other sizes instead?)
> |>     * 1_2_3_4_5  (ditto)
> |>     * 1_234_6789  (do all the groups need to be the same size?)
> |>     * 1_   (must the _ only be in between 2 digits?)
> |>     * 1__234   (what about multiple _s?)
> |>     * 9.876_543_210   (can it be used to the right of the decimal point?)
> |>     * 0xFEFF_0042   (can it be used in hex, octal or binary numbers?)
> |>     * int('123_456')   (do other functions accept this syntax too?)
> |
> | I would say it's ignored.  Have the rule be something like
> | number_string.replace('_','').
> |
> | The only wrinkle is that currently '_1' is usable name, and that
> | should probably be disallowed if the above change took place.
> |
> | I'm +1 on the idea.
>
> Personally I'm be for ignoring the _ also, save that I would forbid it
> at the start or end, so no _1 or 1_.
>
> And I would permit it in hex code etc.
>
> I'm +0.5, myself.
>
As far as I remember, Ada also permits it, but has the rule that it can
occur only between digits. If we follow that, then:

     1_2345_6789 => Yes
     1_2_3_4_5 => Yes
     1_234_6789 => Yes
     1_ => No
     _1 => No
     1__234 => No
     9.876_543_210 => Yes
     9._876_543_210 => No
     9_.876_543_210 => No
     0xFEFF_0042 => Yes
     int('123_456') => Yes