Beside: Difference between revisions

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== Examples ==
== Examples ==
When use [[monadic]]ally, <source lang=apl inline>f∘g</source> behaves the same as [https://en.wikipedia.org/wiki/Function_composition function compositian].
When use [[monadic]]ally, <source lang=apl inline>f∘g</source> behaves the same as an [[atop]].


<source lang=apl>
<source lang=apl>

Revision as of 09:06, 6 September 2021

Beside (), Compose or After is a primitive operator. It shares the glyph with Bind. Called dyadically with function operands f and g, it uses g monadically to pre-processes the right argument before applying f to the given left argument and pre-processed right argument. Called monadically with operands f and g, it applies f to the result of applying g to the argument.

In usage, X f∘g Y is equivalent to X f g Y, and f∘g Y is equivalent to f g Y. Thus, beside can be defined as the dop {⍺←⊢ ⋄ ⍺ ⍺⍺ ⍵⍵ ⍵}.

Examples

When use monadically, f∘g behaves the same as an atop.

      -∘÷ 2 
¯0.5
      ⍝ same as
      -(÷2)
¯0.5

When use dyadically,

      'oy'≡∘⌽'yo'
1
      ⍝ same as
      'oy'≡⌽'yo'
1

When used with Commute, f∘g forms a Hook.

      ≡∘⌽⍨'UwU'
1
      ⍝ same as this, because operator is left-associative, unlike functions which is right-associative
      'UwU'(≡∘⌽)⍨'UwU'
1
      ⍝ same as
      'UwU'≡⌽'UwU'
1

External links

Lessons

Documentation


APL built-ins [edit]
Primitives (Timeline) Functions
Scalar
Monadic ConjugateNegateSignumReciprocalMagnitudeExponentialNatural LogarithmFloorCeilingFactorialNotPi TimesRollTypeImaginarySquare Root
Dyadic AddSubtractTimesDivideResiduePowerLogarithmMinimumMaximumBinomialComparison functionsBoolean functions (And, Or, Nand, Nor) ∙ GCDLCMCircularComplexRoot
Non-Scalar
Structural ShapeReshapeTallyDepthRavelEnlistTableCatenateReverseRotateTransposeRazeMixSplitEncloseNestCut (K)PairLinkPartitioned EnclosePartition
Selection FirstPickTakeDropUniqueIdentityStopSelectReplicateExpandSet functions (IntersectionUnionWithout) ∙ Bracket indexingIndexCartesian ProductSort
Selector Index generatorGradeIndex OfInterval IndexIndicesDealPrefix and suffix vectors
Computational MatchNot MatchMembershipFindNub SieveEncodeDecodeMatrix InverseMatrix DivideFormatExecuteMaterialiseRange
Operators Monadic EachCommuteConstantReplicateExpandReduceWindowed ReduceScanOuter ProductKeyI-BeamSpawnFunction axis
Dyadic BindCompositions (Compose, Reverse Compose, Beside, Withe, Atop, Over) ∙ Inner ProductDeterminantPowerAtUnderRankDepthVariantStencilCutDirect definition (operator)
Quad names Index originComparison toleranceMigration levelAtomic vector