float_to_list(X)

[Richard O'Keefe]

No, making float_to_list/1 a wrapper for format... does not make sense.
float_to_list/1 is meant to give you an accurate representation of the
value.  Two different floats, no matter how small the difference,
should result in different lists.  It's meant for converting a float
to text that you can send to another machine and reconstitute the
same value there.  This will usually result in more digits than a human
would normally want to see.

If you *want* format ~p, use it!

Now perhaps there might be an argument to be made for
float_to_list(X: number(), N: integer()) -> string()
returning a string that represents X as accurately as
possible using N digits.  But that is another discussion.

On Thu, 6 May 2021 at 20:56, Themba Jonga <themba.jonga@REDACTED> wrote:

> Hi, again.
>
> Following a response I got from Dmitry Klionsky, perhaps it makes sense
> for *float_to_list(N)* to be made into a wrapper for
> *lists:flatten(io_lib:format("~p",[N]))?*
>
> Eshell V11.1  (abort with ^G)
> 1> N = 4.4445.
> 4.4445
> 2> lists:flatten(io_lib:format("~p",[N])).
> "4.4445"
> 3> P = 5.4443.
> 5.4443
> 4> lists:flatten(io_lib:format("~p",[P])).
> "5.4443"
> 5> Q = 1.2345678.
> 1.2345678
> 6> lists:flatten(io_lib:format("~p",[Q])).
> "1.2345678"
> 7> float_to_list(Q).
> "1.23456779999999999298e+00"
> 8>
>
> Regards
>
> *Themba Jonga*
>
>
>
>
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> On Wed, 5 May 2021 at 18:38, Scott Ribe <scott_ribe@REDACTED>
> wrote:
>
>> > On May 5, 2021, at 10:20 AM, 2QdxY4RzWzUUiLuE@REDACTED wrote:
>> >
>> > In short, no.
>>
>> Although many (most, actually nearly all) real numbers cannot be
>> represented precisely as a float, any float can be round-tripped to text
>> and back exactly. This is part of the IEEE floating point standard,
>> actually. (And it's not easy...)
>>
>>
>>
>
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