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{{Built-in|Split|↓}} is a [[monadic]] [[primitive function]] which reduces the [[rank]] of its [[argument]] by converting one of its [[axis|axes]] to one level of [[nested array model|nesting]]. The axis to move defaults to the last axis, but a different axis can be chosen using [[function axis]]. It shares its [[glyph]] <source lang=apl inline>↓</source> with the dyadic function [[Drop]]. Split is | {{Built-in|Split|↓}} is a [[monadic]] [[primitive function]] which reduces the [[rank]] of its [[argument]] by converting one of its [[axis|axes]] to one level of [[nested array model|nesting]]. The axis to move defaults to the last axis, but a different axis can be chosen using [[function axis]]. It shares its [[glyph]] <source lang=apl inline>↓</source> with the dyadic function [[Drop]]. Split is the [[inverse]] of [[Mix]] in the sense that the latter undoes the enclosing that Split introduced. | ||
== Examples == | == Examples == | ||
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== Alternatives == | == Alternatives == | ||
Most dialects do not have Split. Instead, | Most dialects do not have Split. Instead, they can use [[Enclose]] (<source lang=apl inline>⊂</source>) with [[bracket axis]] or the [[Rank operator]]: | ||
<source lang=apl> | <source lang=apl> | ||
↓Y | ↓Y | ||
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└────┴────┴────┘ | └────┴────┴────┘ | ||
</source> | </source> | ||
It is common to split a higher-[[rank]] array into its constituent [[major cell]] | It is common to split a higher-[[rank]] array into its constituent [[major cell|major cells]]. The behaviour of Split on matrices might mislead to the belief that this is what the primitive does. However, it isn't so for vectors or arrays of higher rank than 2. Instead, the solution is to use or <source lang=apl inline>⊂[1↓⍳≢⍴Y]Y</source> or <source lang=apl inline>⊂⍤¯1⊢Y</source>: | ||
<source lang=apl> | <source lang=apl> | ||
⊂[1↓⍳≢⍴Y]Y | ⊂[1↓⍳≢⍴Y]Y | ||
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└────┴────┘ | └────┴────┘ | ||
</source> | </source> | ||
== External links == | == External links == | ||
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=== Documentation === | === Documentation === | ||
* [ | * [https://help.dyalog.com/latest/#Language/Primitive%20Functions/Split.htm Dyalog] | ||
{{APL built-ins}}[[Category:Primitive functions]] | {{APL built-ins}}[[Category:Primitive functions]] | ||