But that's optimizing a bad idea...
Which is probably a lot of fun, but still a bad idea.
So here are some other fun takes on this bad idea:
(($,)~ (#~ +./\@:~:&1)@$)
(($,)~ (}.~ i.&0@:=&1)@$)
--
Raul
On Tue, Sep 4, 2012 at 5:13 PM, Henry Rich <henryhr...@nc.rr.com> wrote:
> The combination
>
> ($,)
>
> has special code. If you remove one of the verbs from the hook, you lose
> the special code.
>
> You can use $, to do Raul's job of discarding leading axes of 1:
>
> $ flattensingles =: (($,)~ (}.~ 1&(i.&0@:=))@$) i. 1 1 2 3
> 2 3
>
> Henry Rich
>
>
> On 9/4/2012 2:55 PM, Peter B. Kessler wrote:
>>
>> Henry Rich wrote:
>>>
>>> ''$, ''
>>> |length error
>>>
>>> This one doesn't work when applied to an empty. Sometimes that's
>>> desirable. The others work on empties.
>>>
>>> Note that
>>> '' ($,) A
>>>
>>> has the same result as
>>>
>>> '' $ , A
>>>
>>> but the former version is backed by special code & doesn't actually do
>>> the enfile.
>>>
>>> Henry Rich
>>
>>
>> Does it make sense then to encapsulate this knowledge in a "firstOf" verb
>>
>> firstOfHook =: '' & ($ ,) NB. Does this enfile?
>> B + firstOfHook A NB. Plus of B and the flatten of A.
>> 7 9 11
>>
>> ? How strictly does one have to adhere to the '' ($,) A surface
>> syntax to avoid the enfile?
>>
>> Or (because I find Hooks hard to read) as an At (or, in this case, I
>> could use Atop (@))
>>
>> firstOfAt =: (('' & $) @: ,) NB. Does this enfile?
>> B + firstOfAt A NB. Plus of B and the flatten of A.
>> 7 9 11
>>
>> Either of those gives me a monad that might be useful in its own right
>>
>> firstOfAt A NB. Names make things easier to read.
>> 4
>>
>> in case I was having trouble disentangling the monad on A from the dyad
>> with B in the original problem.
>>
>> ... peter
>>
>>> On 9/3/2012 4:00 AM, Linda Alvord wrote:
>>>>
>>>> Thanks to all!
>>>>
>>>> Kip Murray showed me that I am dealing with a noun that is a table
>>>> and not an atom! His solution ,A turns a list into an atom.
>>>>
>>>> ]A=:1 1$4
>>>> 4
>>>> ]C=:''
>>>> ]B=:3 5 7
>>>> ]B=:3 5 7
>>>> 3 5 7
>>>>
>>>> Two alternatives helped:
>>>>
>>>> B+A
>>>> |length error
>>>> | B +A
>>>> B+{.@,A NB. Bill Lam
>>>> 7 8 9
>>>> B+''$,AN NB. Henry Rich
>>>> 7 8 9
>>>> B+{.,A
>>>> 7 8 9
>>>>
>>>> I add the third because I try to avoid @ and I create the problem
>>>> most often by using {
>>>>
>>>> All work if the noun is empty.
>>>> C+{.@,A
>>>> C+''$,A
>>>> C+{.,A
>>>>
>>>> So this thread really should be called: Table to Atom - First time
>>>> around.
>>>>
>>>> Linda
>>>>
>>>> -----Original Message-----
>>>> From: programming-boun...@forums.jsoftware.com
>>>> [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Henry
>>>> Rich
>>>> Sent: Monday, September 03, 2012 1:16 AM
>>>> To: programm...@jsoftware.com
>>>> Subject: Re: [Jprogramming] Scalar to Vector - Yet again
>>>>
>>>> The easiest way to make a scalar of an arbitrary noun is
>>>>
>>>> ''($,)A
>>>>
>>>> which will work on anything except an empty A.
>>>>
>>>> Henry Rich
>>>>
>>>> On 9/2/2012 10:52 PM, Roger Hui wrote:
>>>>>
>>>>> You are (probably) trying to undo years of conditioning in APL, which
>>>>> has the misguided "singleton extension": In APL,
>>>>> 2 3 4 + (?n⍴1)⍴5
>>>>> worked. Singleton extension is undesirable because it complicates the
>>>>> rules for the rank operator.
>>>>>
>>>>>> It feels wrong to have to do things like this every time I want to
>>>>>> use the result of a previous computation called A .
>>>>>
>>>>>
>>>>> Alternatively, it feels wrong that A is non-scalar as computed.
>>>>>
>>>>>
>>>>>
>>>>> On Sun, Sep 2, 2012 at 6:48 PM, Linda Alvord
>>>>> <lindaalv...@verizon.net>wrote:
>>>>>
>>>>>> I finally think I know what I don't know. I want to turn "table" A
>>>>>> into a scalar (which it happens to look like).
>>>>>>
>>>>>> A
>>>>>> 4
>>>>>> $A
>>>>>> 1 1
>>>>>> B=:3 5 7
>>>>>> A+B
>>>>>> |length error
>>>>>> | A +B
>>>>>> (,A)+B
>>>>>> |length error
>>>>>> | (,A) +B
>>>>>> (,3$A)+B
>>>>>> 7 9 11
>>>>>> (,($B)$A)+B
>>>>>> 7 9 11
>>>>>>
>>>>>> It feels wrong to have to do things like this every time I want to
>>>>>> use the result of a previous computation called A .
>>>>>>
>>>>>> Linda
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: programming-boun...@forums.jsoftware.com
>>>>>> [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of Linda
>>>>>> Alvord
>>>>>> Sent: Saturday, September 01, 2012 7:26 PM
>>>>>> To: programm...@jsoftware.com
>>>>>> Subject: Re: [Jprogramming] Scalar to Vector - Yet again
>>>>>>
>>>>>> I wasn't thinking. A isn't a scalar. I even knew it had shape 1 1 .
>>>>>>
>>>>>> A
>>>>>> 4
>>>>>> $A
>>>>>> 1 1
>>>>>> $3 2
>>>>>> 2
>>>>>> 2$A
>>>>>> 4
>>>>>> 4
>>>>>> 3 2 + ,2$A
>>>>>> 7 6
>>>>>>
>>>>>> This works! Thanks.
>>>>>>
>>>>>> Linda
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: programming-boun...@forums.jsoftware.com
>>>>>> [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of km
>>>>>> Sent: Saturday, September 01, 2012 6:10 PM
>>>>>> To: programm...@jsoftware.com
>>>>>> Subject: Re: [Jprogramming] Scalar to Vector - Yet again
>>>>>>
>>>>>> ,4 is a vector
>>>>>>
>>>>>> Sent from my iPad
>>>>>>
>>>>>>
>>>>>> On Sep 1, 2012, at 4:56 PM, "Linda Alvord" <lindaalv...@verizon.net>
>>>>>> wrote:
>>>>>>
>>>>>>> I vow to remember how to do this, and several months later I forget
>>>>>>> and can't find it
>>>>>>>
>>>>>>> anywhere. Is there some way to get to the example from the
>>>>>>> vocabulary
>>>>>>
>>>>>> page?
>>>>>>>
>>>>>>> Maybe I can remember that.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> A=:1 1$4
>>>>>>>
>>>>>>> 3 2 + A
>>>>>>>
>>>>>>> |length error
>>>>>>> | 3 2 +A
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Thanks.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Linda
>>>>>>>
>>>>>>> --------------------------------------------------------------------
>>>>>>> -- For information about J forums see
>>>>>>> http://www.jsoftware.com/forums.htm
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