SplitPoints2

If you have something like this:

      1 2 3

and you want transform this into

      1 0 1 0 0 1 0 0 0

than this is your phrase:

      ∊(IV+1)↑¨1

Examples

      ⎕FX ⍕2 1⍴'r←SplitPoints2 IV' 'r←∊(IV+1)↑¨1'    ⍝ This will work in any APL dialect
      SplitPoints2 3 1 2
1 0 0 0 1 0 1 0 0 
      SplitPoints2 2 9 11 5
1 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 

Specialties

You might expect this expression:

      (,1,[⎕IO+0.5]-,IV)/1

to be less expensive but at least in Dyalog it's the other way round: it's 31% faster. Besides, the expression does not work in NARSS2000 which does not accept negative arguments to /.

Compatibility

Checked with: Dyalog, NARS2000, APLX APL2, APL+Win - Add as many as you can/like

Test Cases

Replace "PhraseName" accordingly Show Hide test cases test cases

Test
 ⎕IO←0      ⍝ You may change this; however, zero IS the default in the Phrasebook
⍝⎕ML←3      ⍝ Enable this line in Dyalog APL if appropriate
 ⎕FX'r←SplitPoints2 IV' 'r←∊(IV+1)↑¨1'
⍝ ---- Start Test cases (do not delete this!)
1 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0  ≡ SplitPoints2 2 9 11 5
(,1) ≡ SplitPoints2 0
1 0 1 0 1 0 ≡ SplitPoints2 1 1 1 
1 0 0 1 0 0 0 ≡ SplitPoints2 2 3
1 0 0 1 1 0 0 0 ≡ SplitPoints2 2 0 3
⍬≡ SplitPoints2 ⍬

Test my code, both Examples and Test Cases.

See also: SplitPoints1

Mentor: KaiJaeger

Tags are used to create a list automatically - see ListAllTags Tags: <SplitPoints>

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