[Jprogramming] Indexing into array

[Henry Rich]

It's in NuVoc:

http://www.jsoftware.com/jwiki/Vocabulary/curlylf#dyadic

Henry Rich

On 5/29/2014 6:44 AM, alexgian wrote:
> Oops, scratch that, just saw it.
>
>
> On 29 May 2014 11:39, alexgian <alexgian at blueyonder.co.uk> wrote:
>
>> Thanking you kindly, sir, that's a relief!
>> Seems to work at all ranks, too.
>> I don't think it's in the Voc (under { ), or my eyesight is getting really
>> bad.  Should be, IMHO, fairly crucial thing for an array-programming
>> language.
>>
>>
>>
>> On 29 May 2014 11:23, Kip Murray <thekipmurray at gmail.com> wrote:
>>
>>>     i. 4 4
>>>   0  1  2  3
>>>   4  5  6  7
>>>   8  9 10 11
>>> 12 13 14 15
>>>     (<2 1) { i. 4 4
>>> 9
>>>
>>>
>>> On Thursday, May 29, 2014, alexgian <alexgian at blueyonder.co.uk> wrote:
>>>
>>>> If I want to index into a (rank 2) array to get the element usually
>>> called
>>>> the (i,j)th in the big, bad world, is there a better way to do it than
>>>> this, which I currently use?
>>>>
>>>>      idx  =: (1 { [) { ] {~ 0 { [
>>>>
>>>>      2 1 idx 4 4 $i.16
>>>>
>>>> 9
>>>>
>>>> I notice that if { takes an array as left arg, it merely returns the
>>> given
>>>> rows of that array, rather than the required indexed element.
>>>> So I can't do, for instance,  (2 1) { 4 4 $i.16 and get what I want
>>>> Furher, I wander if there is a more generic way of writing this so that
>>> it
>>>> would work automatically for rank-3 arrays and greater.
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>>>
>>>
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>>
>>
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