Scalar extension: Difference between revisions

Dyadic [[scalar functions]] and the [[Each operator]] use scalar extension to pair their arguments:

       1 2 3 4 * 2

1 4 9 16

[[Replicate]] and [[Expand]] extend a scalar left argument to apply to each element of the right argument:

       2/'abc'

aabbcc

[[APL2]] and [[Dyalog APL]] use a variant of singleton extension when the selected axis of the right argument has length one: each element along that axis is reused for every element of the left argument.

       ⍴ 2 ¯3 /[2] 7 1 8⍴⍳56

7 5 8

In languages which allow a vector left argument to [[Rotate]], the behavior with a scalar left argument follows from scalar extension. In the following example a length-2 vector could be used to rotate each row by a different amount. A scalar rotates both rows by the same amount.

       3⌽2 6⍴'extendscalar'

endext

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