[Jprogramming] Fwd: 16bHHHHHHHH...HHx - no way

[David Lambert]

Since 36 characters are available to write digits, we would not expect a 
number written in a base be extended.

    10bx
33

    datatype 10bx
integer

    10b.x        NB. floating point
3.3


j probably could permit an extended vector

    {:0x  16b53973c0482de06eddf68d4531e9062c7
|ill-formed number


Finally,

    16x#.16b5 16b3 16b9 16b7 16b3 16bc 16b0 16b4 16b8 16b2 16bd 16be 
16b0 16b6 16be 16bd 16bd 16bf 16b6 16b8 16bd 16b4 16b5 16b3 16b1 16be 
16b9 16b0 16b6 16b2 16bc 16b7
111111177777777111111111777777771111111

    16x#.(Num_j_,26}.Alpha_j_)i.'53973c0482de06eddf68d4531e9062c7'
111111177777777111111111777777771111111





On 06/17/2016 08:00 AM, programming-request at forums.jsoftware.com wrote:
> Message: 1
> Date: Fri, 17 Jun 2016 13:52:52 +0300
> From: Moon S <moon.aka.sun at gmail.com>
> To: programming <programming at jsoftware.com>
> Subject: [Jprogramming] Fwd:  16bHHHHHHHH...HHx - no way
> Message-ID:
> 	<CAG++_noovUYWrrgk+21bD+Bmc8qA0C1XYpWhf7KuL6hwn8fdXw at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> It seems that there's no extended hexadecimal literals in J.
>
>
> The decimal ones work ok. Let's convert a long integer to its hex
> representation
>
>     '0123456789abcdef'{~16#.^:_1 (111111177777777111111111777777771111111x)
> 53973c0482de06eddf68d4531e9062c7
>
>     16b53973c0482de06eddf68d4531e9062c7      NB. no, it will be a usual float
> 1.11111e38
>     16b53973c0482de06eddf68d4531e9062c7x     NB. no, 'x' is just a (wrong)
> digit
> 1.77778e39
>     x:16b53973c0482de06eddf68d4531e9062c7    NB. nope
> 111111177777777116167868047726401814528
>     x:'16b53973c0482de06eddf68d4531e9062c7'  NB. you wish! :)
> |domain error
> |       x:'16b53973c0482de06eddf68d4531e9062c7'
>
> But sure one can convert a vector of small hex numbers, although it
> requires writing '16b' for each of them:
>
>     (2^32x)#. 16b53973c04 16b82de06ed 16bdf68d453 16b1e9062c7
> 111111177777777111111111777777771111111
>
> Or convert a string:
>
>     X=:16x#.'0123456789abcdef'i.]                   NB. it's like dfh but
> for extended ints
>     X'53973c0482de06eddf68d4531e9062c7'     NB. Hello IBM!
> 111111177777777111111111777777771111111
>
> Or treat pre-formatted strings, as they are usually written in some
> documentation, for example, test cases for encryption. And this is 4.5
> times faster, than the previous method (J 8.04 64-bit, Windows).
>
>     (2^32x)#. ".&('16b'&,)&> ' 'splitstring '53973c04 82de06ed df68d453
> 1e9062c7'
> 111111177777777111111111777777771111111
>
>
> ---
> Georgiy Pruss
>
>
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