From 228e1b6d9d60eb885e5cda1b2c05048b253e140d Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Sun, 4 Jul 2021 22:34:44 -0400 Subject: Diagram and introduction for search functions --- docs/doc/search.html | 126 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 126 insertions(+) create mode 100644 docs/doc/search.html (limited to 'docs') diff --git a/docs/doc/search.html b/docs/doc/search.html new file mode 100644 index 00000000..118cd35a --- /dev/null +++ b/docs/doc/search.html @@ -0,0 +1,126 @@ + + + + BQN: Search functions + +
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Search functions

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The three search functions are Index of (⊐), Progressive Index of (⊒), and Member of (∊). These are dyadic functions that search one argument ("searched-in") for major cells matching cells from the other ("searched-for"). For example, Index of returns, for each cell in 𝕩, the index of the first cell in 𝕨 that matches it.

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NameforinReturn
⊐Index of𝕩𝕨Index of first match
⊒Progressive Index of𝕩𝕨Index of first unused match
∊Member of𝕨𝕩1 if found, 0 if not
⍋⍒Bins𝕩𝕨Predecessor index
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The searched-for argument is 𝕩 in Index-of functions (⊐⊒) and 𝕨 in Member of (∊). Bins Up and Down (⍋⍒) are ordering functions but follow the same pattern as Index-of. It's split into cells, but not necessarily major cells: instead, the cells used match the rank of a major cell of the other (searched-in) argument. In the most common case, when the searched-in argument is a list, 0-cells are used for the search (we might also say elements, as it gives the same result).

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The result is always an array containing one number for each searched-for cell. For Index of and Member of, every result is computed independently; for Progressive Index of the result for a cell can depend on earlier cells, in index order.

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