Prefix: Difference between revisions

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Prefix and Suffix vectors now have a page
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(Prefix and Suffix vectors now have a page)
 
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In [[leading axis theory]], the [[frame]] for k-cells of an array is a prefix of that array's [[shape]], while the [[cell shape]] is a [[suffix]].
In [[leading axis theory]], the [[frame]] for k-cells of an array is a prefix of that array's [[shape]], while the [[cell shape]] is a [[suffix]].


[[Iverson notation]] included the notion of a prefix vector <math>\alpha^j(n)</math> consisting of <math>j</math> ones followed by <math>n-j</math> zeros; such a vector could be used to produce a length-<math>j</math> prefix of a length-<math>n</math> vector using [[Compress]]. A prefix function <syntaxhighlight lang=apl inline>n ⍺ j</syntaxhighlight> was included in early versions of [[APL\360]].
[[Iverson notation]] and very early APLs included the notion of a [[prefix vector]] <math>\alpha^j(n)</math> consisting of <math>j</math> ones followed by <math>n-j</math> zeros; such a vector could be used to produce a length-<math>j</math> prefix of a length-<math>n</math> vector using [[Compress]].


In [[Dyalog APL]]'s [[Total array ordering]], a prefix of another array always orders earlier than that array; this is a consequence of the principally "nothing is less than something" used as the foundation for Dyalog's TAO.
In [[Dyalog APL]]'s [[Total array ordering]], a prefix of another array always orders earlier than that array; this is a consequence of the principally "nothing is less than something" used as the foundation for Dyalog's TAO.


[[Category:Array relationships]]
[[Category:Array relationships]]

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