x:".s first computes ".s, which is a floating-point approximation of the
number represented by s, and _then_ converts that floating-point approximation
to an extended precision value. (The latter conversion may also be
approximate, pursuant to comparison tolerance, but is always exact when
applied to floating-point values with no fractional part, as is the case
here.)
It is the same as if you had written x:34823742834835345345345346546454237;
the number is approximated before x: has a chance to get at it.
On Sun, 24 Apr 2022, Thomas Bulka wrote:
Hi Raul,
alas, you are right. Say, I have the following string:
s =: '34823742834835345345345346546454237'
Since x: does not accept strings as arguments I first tried to convert
s into an integer before casting it to extended int, as you showed
before. However, this gives me the wrong result, while my first
approach yields the correct result.
x:@:". s NB. 34823742834835345123208419344384000
".@:,&'x' s NB. 34823742834835345345345346546454237
I don't quite understand the behaviour of the first line, though.
Regards,
Thomas
Am So., 24. Apr. 2022 um 01:51 Uhr schrieb Raul Miller <rauldmil...@gmail.com>:
I do not think you get the same results using x:
I think your ".@,&'x'@> data was fine.
You could use 10#.x:".@>@> data if you don't mind the speed penalty
and excessive use of memory, but x:".@> data does not give the same
answer, and as far as I know, x: does not accept string arguments.
Am I missing something?
Thanks,
--
Raul
On Sat, Apr 23, 2022 at 6:46 PM Thomas Bulka
<thomas.bu...@constraintegic.net> wrote:
>
> Sorry for the noise,
>
> question can be revoked, since I found x: ...
>
> Regards,
>
> Thomas
>
> Am Sa., 23. Apr. 2022 um 23:54 Uhr schrieb Thomas Bulka
> <thomas.bu...@constraintegic.net>:
> >
> > Hello everyone,
> >
> > say, I have a boxed list of strings which represent large integers
> > (originally I imported the data from a text file):
> >
> > data =:
'34823742834835345345345346546454237';'34593823489289342893498945349539'
> >
> > I want to convert the character data into integers to use them for
> > computations, but ". gives me non-extended integers, so:
> >
> > ".@> data NB. 3.48237e34 3.45938e31
> >
> > I know, of course, that I can construct an extended integer by means
> > of adding a trailing x to an integer literal. I wonder, however, how
> > this can be done automatically. I managed to get the result I want by
> > adding the trailing 'x' to the character arrays before using ". on
> > them:
> >
> > ".@,&'x'@> data NB. Works as desired
> >
> > However, intuitively this seems to be a quite strange solution and I
> > hope there is a verb which can be used to explicitly convert the
> > character strings into extended integers. Unfortunately, I've not been
> > able to find it.
> >
> > Any suggestions on this?
> >
> > Regards,
> >
> > Thomas
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