[Python-ideas] float('∞')=float('inf')

[Joshua Landau]

On 12 July 2013 15:46, Laurens Van Houtven <_ at lvh.io> wrote:
> On Fri, Jul 12, 2013 at 4:43 PM, Gerald Britton <gerald.britton at gmail.com>
> wrote:
>>
>> Man I don't know how you are doing this!  I just tried:
>>
>> float('<greek letter pi>') and got
>>
>> Value error: could not convert string to float '<greek letter pi>'
>>
>> For that matter, I can't figure out how to type the greek letter for
>> pi in gmail!  Guess I have some things to learn.
>>
>> So, if Python doesn't recognize the symbol for pi, why should it
>> recognize the one for infinity?
>
>
> The example he posted is of digits, not of any particular symbol for a
> constant. The difference, obviously, is that you can't write infinity as a
> bunch of digits, whereas you can at least approximate pi with any number of
> digits.

Ahem:

>>> float("1"*310)
inf

Just because.

My personal reason for thinking that unicode infinity is reasonable
whereas unicode pi/tau/phi/etc. is not, is simply that we *already*
special-case infinity. We do not do so for other mathematical
constants. Additionally, Pi only holds the value of half the circle
constant by default -- other branches of mathematics uses for other
things and some use it as a variable. They are rare, granted, but Pi
is not as clear cut as, say, "9" or "infinity".