Re: [Bug-apl] Help with APL expression

[Christian Robert]

That kind of expression really get me on my knees.

thanks for sharing,

Xtian.


On 2017-07-06 17:54, Ala'a Mohammad wrote:
> Oops, the second solution should be
>
>   (1+c[x]) ⊂ s[x←⍋c]
>
> Ala'a
>
> On Fri, Jul 7, 2017 at 1:38 AM, Ala'a Mohammad <address@hidden> wrote:
> > Hi,
> > Another two ways, Not as compact or optimized, but generate the same output
> > 1)
> > G groups, C categories, and S strings
> >
> > G←(⍴∪C)⍴⊂⍬ ◊ C {G[⍺]←⊂(⊃G[⍺]),⊂⍵}¨S ◊ G
> >
> > I forgot how to suppress the middle output
> > or in a function
> >
> > ∇ groups ← categories group items
> >    groups ← (⍴∪categories)⍴⊂⍬
> >    categories {groups[⍺]←⊂(⊃groups[⍺]),⊂⍵}¨ items
> >
> > 2)
> > (1+C[x]) ⊂ S[(⍳⍴C)[x←⍋C]]
> >
> > Best wishes,
> >
> > Ala'a
> >
> > On Wed, Jul 5, 2017 at 2:48 PM, Louis de Forcrand <address@hidden> wrote:
> > > Is it important that they be grouped in the order specified by the key?
> > > If not, this should do (with C the categories and S the strings):
> > >
> > > (⊂[1]C∘.=∪C)/¨⊂S
> > >
> > > If they must be ordered, then this can do it:
> > >
> > > (⊂[1]C∘.=U[⍋U←∪C])/¨⊂S
> > >
> > > In addition, the categories don’t have to be numbers.
> > >
> > > Note that Dyalog’s (dyadic) key function is equivalent to this, with L being
> > > the operator’s left operand:
> > >
> > > L¨(⊂[1]C∘.=∪C)/¨⊂S
> > >
> > > Cheers,
> > > Louis
> > >
> > > On 05 Jul 2017, at 11:43, Elias Mårtenson <address@hidden> wrote:
> > >
> > > I have a list of strings, and a corresponding set of categorisations:
> > >
> > >        strings ← 'foo' 'bar' 'abc' 'def' 'ghi' 'jkl'
> > >        categories ← 1 1 0 2 1 0
> > >
> > > I now need to group these strings according to category. In other words,
> > > when applying operation X, I need the following output:
> > >
> > >        categories X strings
> > > ┏→━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
> > > ┃┏→━━━━━━━━━━┓ ┏→━━━━━━━━━━━━━━━━┓ ┏→━━━━┓┃
> > > ┃┃"abc" "jkl"┃ ┃"foo" "bar" "hgi"┃ ┃"def"┃┃
> > > ┃┗∊━━━━━━━━━━┛ ┗∊━━━━━━━━━━━━━━━━┛ ┗∊━━━━┛┃
> > > ┗∊∊━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
> > >
> > > What is the best way to solve this?