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Miraheze>Marshall (→History: Describe use in A Programming Language) |
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== History == | == History == | ||
In [[A Programming Language]], prefix and suffix operations were described using the syntax <code>⍺<sup>j</sup>/x</code> to take the first <code>j</code> elements of vector <code>x</code> and <code>⍵<sup>j</sup>/x</code> for the last <code>j</code> elements. This combined a use of the special prefix and suffix vectors <code>⍺<sup>j</sup>(n)</code> and <code>⍵<sup>j</sup>(n)</code> with [[Compress|compression]], with the length <code>n</code> inferred based on the length of <code>x</code>. The symbol <code>↑</code> was used for vector [[Rotate]], while <code>↓</code> rotated in the opposite direction. <ref>Iverson, Kenneth E. (1962). A Programming Language. Wiley. ISBN 978-0-471-43014-8.</ref> | |||
Take using the symbol <code>↑</code> was first present in [[APL\360]]. | |||
The [[Function axis|axis]] specification for Take was defined in [[APL2]]. It is shared by [[SHARP APL]] and [[Rationalized APL]], and continues to be supported in [[Dyalog APL]]. | The [[Function axis|axis]] specification for Take was defined in [[APL2]]. It is shared by [[SHARP APL]] and [[Rationalized APL]], and continues to be supported in [[Dyalog APL]]. | ||