Er...
mat=:((_2{. 1 1,$) $ ])
$mat i.5 2
5 2 2
... maybe not quite that, at least not for this case?
Thanks,
--
Raul
On Fri, Oct 2, 2015 at 9:48 PM, Rob Hodgkinson <[email protected]> wrote:
> Further to Bill’s point Nollaig, your approach using rank fails for a rank 0
> item …
>
> $ ,:`]@.(<:@$^:2 fee) fee=:'ab'
> 1 2
> $ ,:`]@.(<:@$^:2 fee) fee=:,'a'
> 1 1
> $ ,:`]@.(<:@$^:2 fee) fee=:'a'
>
>
> For this solution maybe better to just use $ rather than ,: as shown (easier
> to follow and efficient):
> $(_2{. 1 1,$ fee)$fee=:'ab'
> 1 2
>
> so …
> mat=:((_2{. 1 1,$) $ ]) NB: Note in the left tine of the fork (_2{. 1
> 1,$) the argument is supplied by definition of the fork
> $mat 'ab'
> 1 2
> $mat ,'a'
> 1 1
> $mat 'a'
> 1 1
>
> Rob
>
>> On 3 Oct 2015, at 11:28 am, bill lam <[email protected]> wrote:
>>
>> $$ looks like a scalar but is a rank 1 array. use #$ instead.
>> ,:`]@.(<:@#@$) fee=:'ab'
>>
>> the verb
>> ,:`]@.(<:@$^:2 fee) is reduced to ] and then run as ] fee
>> On Oct 3, 2015 8:27 AM, "Nollaig MacKenzie" <[email protected]>
>> wrote:
>>
>>>
>>>
>>> I have a variable, fee, which might have shape
>>> N,2 or just 2. I want a function that converts
>>> fee when it has shape 2 to shape 1 2.
>>>
>>> It seems straightforward: if the rank is 2,
>>> make no change, if 1, apply ,:
>>>
>>> So something like ,:`]@.(<:@$^:2) should
>>> do the trick. Indeed, this works:
>>>
>>> $ ,:`]@.(<:@$^:2 fee) fee=:'ab'
>>> 1 3
>>>
>>> But when I try to define something to do
>>> what I want, I get lost.
>>>
>>> ,:`]@.(<:@$^:2) fee=:'ab'
>>> |rank error
>>> | ,:`]@.(<:@$^:2)fee=:'ab'
>>> ,:`]@.(<:@$^:2 ]) fee=:'ab'
>>> |domain error
>>> | ,:`]@.(<:@$^:2]) fee=:'ab'
>>> ,:`]@.((<:@$^:2)@: ]) fee=:'ab'
>>> |rank error
>>> | ,:`]@.((<:@$^:2)@:]) fee=:'ab'
>>>
>>>
>>>
>>> (I'll spare you more)
>>>
>>> I must be missing something obvious.
>>>
>>> --
>>> Nollaig MacKenzie
>>> http://www.yorku.ca/nollaig
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>>> For information about J forums see http://www.jsoftware.com/forums.htm
>>>
>> ----------------------------------------------------------------------
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>
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