Code example for first 10 odd numbers on APL is incorrect

[herwinw]

It looks like ⍳ in APL starts at 1 instead of 0, the code snippet linked in the readme generates the sequence, 3, 5 .. 21

[juntuu]

I think it just assumes index origin to be set to zero.

      ⎕IO←0
      ⍳4
0 1 2 3

[herwinw]

I tried the Runnable link from the README, that iota is 1-indexed for me. I'm not sure whether that's a global default, or it saves something in cookies which causes the result to differ depending on that.

[juntuu]

Since TryAPL has index origin 1 by default, some possible fixes would be:

• Subtract one instead of adding (as the R sample does)

  ¯1+2×⍳10

• or set the index origin to zero first in the linked snippet (the sharable link unfortunately needs to fit on one line)

  ⎕IO←0 ⋄ 1+2×⍳10
  1+2×⍳10 ⊣ ⎕IO←0

[codereport]

We decided to go with ¯1+2×⍳10. Thanks for pointing this out.