From 2afb23928e1984d475cc460e1672e8f6fa0e4dbe Mon Sep 17 00:00:00 2001 From: Marshall Lochbaum Date: Wed, 11 Aug 2021 17:21:31 -0400 Subject: Allow clicking on header to get fragment link --- docs/doc/search.html | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'docs/doc/search.html') diff --git a/docs/doc/search.html b/docs/doc/search.html index accd54fa..7834a06d 100644 --- a/docs/doc/search.html +++ b/docs/doc/search.html @@ -4,7 +4,7 @@ BQN: Search functions
(github) / BQN / doc
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Search functions

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Search functions

@@ -133,7 +133,7 @@

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).

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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Member of

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Member of

The simplest of the search functions, Member of (∊) returns 1 if an entry in 𝕨 matches some entry in 𝕩, and 0 if it doesn't.

↗️
    "green"‿"bricks"‿"cow"‿"blue" ∊ "red"‿"green"‿"blue"
 ⟨ 1 0 0 1 ⟩
@@ -147,7 +147,7 @@
 "tal st"

These are the APL functions Intersect (∩) and Without (~). Really, only 𝕩 is treated like a set, while the ordering and multiplicity of elements of 𝕨 are maintained. I think the explicit implementations show this well, since 𝕩 is only used as the right argument to ∊, and prefer this clarity to the brevity of a single symbol.

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Index of

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Index of

Index of (⊐) returns the index of the first occurrence of each entry in 𝕨, or ≠𝕨 if an entry doesn't appear in 𝕨 at all.

↗️
    "zero"‿"one"‿"two"‿"three" ⊐ "one"‿"eight"‿"two"
 ⟨ 1 4 2 ⟩
@@ -160,7 +160,7 @@
     "letters" (<∘/˘≡⌜˜) "let"  # Many to many
 ⟨ ⟨ 0 ⟩ ⟨ 1 4 ⟩ ⟨ 2 3 ⟩ ⟩
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Progressive Index of

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Progressive Index of

Progressive Index of (⊒), as the name and glyph suggest, is a more sophisticated variant of Index of. Like Index of, it returns either ≠𝕨 or an index of a cell from 𝕨 that matches the given cell of 𝕩. Unlike Index of, no index except ≠𝕨 can ever be repeated. Progressive Index of returns the index of the first unused match, provided there's still one left.

↗️
    "aaa" ⊒ "aaaaa"
 ⟨ 0 1 2 3 3 ⟩
@@ -192,7 +192,7 @@
 ↗️
    ⊒˜ "anything at all"
 ⟨ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 ⟩
 

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+
 
Search functions are designed to search for multiple elements at once, and return an array of results. This is the array-oriented way to do it, and can allow faster algorithms to be used for the computation.

 ↗️
    stuff ← "tacks"‿"paper"‿"string"‿"tape"
 
@@ -218,7 +218,7 @@
 2
 

 
For Member of, the equivalent is ∊⟜stuff⌾<.

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Higher ranks

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Higher ranks

 
So far we've shown search functions acting on lists. Well, and one example with a unit array slipped into the last section. In fact, if the searched-in array is a list, then the searched-for argument can have any rank.

 ↗️
    ("high"≍"rank") ∊ "list arg"
 ┌─         
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