I was about to send something when we had to go out for a bit...
My best so far is
((] #~ 1 = I.)~ (0 _1 + ])) ~
assuming I've copied it correctly...
Mike
Please reply to [email protected].
Sent from my iPad
> On 24 Sep 2017, at 18:45, Skip Cave <[email protected]> wrote:
>
> Marshall,
>
> Wow! that is neat! I hadn't really understood dyadic I. but this forced me
> to try to understand it:
>
> 8 100 (]#~1=I.) 2 10 45 300
>
> 10 45
>
> 8 100 I. 2 10 45 300
>
> 0 1 1 2
>
> 1 = 8 100 I. 2 10 45 300
>
> 0 1 1 0
>
> (1 = 8 100 I. 2 10 45 300) # 2 10 45 300
>
> 10 45
>
> 8 100 I. 2 10 45 300
>
> 0 1 1 2
>
> 1 8 100 I. 2 10 45 300
>
> 1 2 2 3
>
> 1 8 100 I. 2 10 45 300 450
>
> 1 2 2 3 3
>
> 1 8 100 350 I. 2 10 45 300 450
>
> 1 2 2 3 4
>
> 1 8 100 350 I. 300 2 45 10 450
>
> 3 1 2 2 4
>
> So now I'm getting a feel for I. Reading the terse Vocabulary description
> of dyadic I. didn't help much in making the I. functionality clear, at
> least for me. The NuVoc description wasn't much more helpful, but the
> examples after the description in Nuvoc cleared things up considerably.
>
> Also, the dissect tool was very helpful in figuring out how J parsed the
> whole dyadic verb. Who is the author of the dissect tool? That's a great
> help in learning J.
>
> Skip
>
> Skip Cave
> Cave Consulting LLC
>
> On Sun, Sep 24, 2017 at 3:14 AM, Marshall Lochbaum <[email protected]>
> wrote:
>
>> Try
>>
>> rng =: ] #~ 1=I.
>>
>> it's about half as fast because I. is not very well-optimized.
>>
>> Marshall
>>
>>> On Sun, Sep 24, 2017 at 02:29:31AM -0500, Skip Cave wrote:
>>> Here's a function I came up with to select numbers in a vector which are
>>> within some range.
>>>
>>> Find all the numbers between 10 & 100 in a set of random numbers from 0
>> to
>>> 200:
>>>
>>>
>>> rng =. 4 : '((({.x)</y)*.(({:x)>/y))#y'
>>>
>>>
>>> 10 100 rng ?50$200
>>>
>>> 89 91 32 85 84 27 31 20 28 66 96 93 22 85 39 97 82 35 90 67 34 35 67 95
>> 50
>>>
>>>
>>> Between 120 & 180:
>>>
>>>
>>> 120 180 rng ?50$200
>>>
>>> 148 163 133 165 150 178 121 146 161 179
>>>
>>>
>>> Is there a more concise/efficient way to select numbers in a range?
>>>
>>> Skip Cave
>>> Cave Consulting LLC
>>> ----------------------------------------------------------------------
>>> For information about J forums see http://www.jsoftware.com/forums.htm
>> ----------------------------------------------------------------------
>> For information about J forums see http://www.jsoftware.com/forums.htm
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
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