Partitioned Enclose

From APL Wiki
Jump to navigation Jump to search

Partitioned Enclose () is a dyadic function which splits its right argument into differently sized pieces as determined by the left argument.

Basic functionality

In the simplest case, and on a vector right argument, the corresponding element in the left argument indicates where divisions begin:

      1 0 1 0 0 0 0'HiEarth'

Non-Boolean left argument

Almost all dialects restrict the left argument to provide only the above functionality. However, the left argument can be interpreted as a count of how many partitions begin with a particular position:

      2 0 3 0 0 0 0'HiEarth'

Short left argument

The dialects that support this extension also allow omission of trailing zeros, which is useful if the partitioning vector is generated by where's inverse:

      ¯11 1 3 3 3
2 0 3
      2 0 3'HiEarth'

Long left argument

Additional trailing empty divisions are created by adding an additional division count corresponding to the position beyond the end of the right argument:

      1 0 1 0 0 0 0 1'HiEarth'

Split into lengths

This above extensions allow a simple definition of a split-into-lengths function:

Try it online!

      Split{  ¯1 +\ ¯11,}
      3 3 4 Split 'HowAreYou?'

See also

External links



APL built-ins [edit]
Primitive functions
Monadic ConjugateNegateSignumReciprocalMagnitudeExponentialNatural LogarithmFloorCeilingFactorialNotPi TimesRollTypeImaginarySquare Root
Dyadic AddSubtractTimesDivideResiduePowerLogarithmMinimumMaximumBinomialComparison functionsBoolean functions (And, Or, Nand, Nor) ∙ GCDLCMCircularComplexRoot
Structural ShapeReshapeTallyDepthRavelEnlistTableCatenateReverseRotateTransposeRazeMixSplitEncloseNestCut (K)PairLinkPartitioned EnclosePartition
Selection FirstPickTakeDropUniqueIdentitySelectReplicateExpandSet functions (IntersectionUnionWithout) ∙ Bracket indexingIndex
Selector Index generatorGradeIndex OfInterval IndexIndicesDeal
Computational MatchNot MatchMembershipFindNub SieveEncodeDecodeMatrix InverseMatrix DivideFormatExecuteMaterialiseRange
Primitive operators Monadic EachCommuteConstantReplicateExpandReduceWindowed ReduceScanOuter ProductKeyI-beamSpawnFunction axis
Dyadic BindCompositions (Compose, Reverse Compose, Beside, Withe, Atop, Over) ∙ Inner ProductPowerAtUnderRankDepthVariantStencilCut (J)
Quad names
Arrays Index originMigration levelAtomic vector
Functions Name classCase convertUnicode convert
Operators SearchReplace