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diff --git a/doc/selfcmp.md b/doc/selfcmp.md index fdb43090..e4f1616c 100644 --- a/doc/selfcmp.md +++ b/doc/selfcmp.md @@ -1,6 +1,6 @@ *View this file with results and syntax highlighting [here](https://mlochbaum.github.io/BQN/doc/selfcmp.html).* -# Self-comparison functions +# Self-search functions <!--GEN d ← 48‿22 @@ -39,20 +39,20 @@ defs ← "defs" Enc ("mask"At"id=m") Enc ⟨ ⟩ --> -BQN has four self-comparison functions, Classify (`⊐`), Occurrence Count (`⊒`), Mark Firsts (`∊`), and Deduplicate (`⍷`). Each of these is a monadic function that obtains its result by comparing each major cell of the argument (which must have rank at least 1) to the earlier major cells with [match](match.md). For example, Mark Firsts indicates the cells that don't match any earlier cell, making them the first of their kind. +BQN has four self-search functions, Classify (`⊐`), Occurrence Count (`⊒`), Mark Firsts (`∊`), and Deduplicate (`⍷`). Each of these is a monadic function that obtains its result by comparing each major cell of the argument (which must have rank at least 1) to the earlier major cells with [match](match.md). For example, Mark Firsts indicates the cells that don't match any earlier cell, making them the first of their kind. ∊ "abaacb" -When the argument is a list, its major cells are units and thus contain one element each, so it's just as valid to say that a self-comparison function compares elements of its argument. Only with a higher-rank argument does the major cell nature become apparent. +When the argument is a list, its major cells are units and thus contain one element each, so it's just as valid to say that a self-search function compares elements of its argument. Only with a higher-rank argument does the major cell nature become apparent. ⊢ arr ← >"abc"‿"dcb"‿"abc"‿"bcd"‿"dcb" ∊ arr -The result has one number for each major cell, or in other words is a list with the same length as its argument. Three self-comparison functions follow this pattern, but Deduplicate (`⍷`) is different: it returns an array of the same rank but possibly a shorter length than the argument. +The result has one number for each major cell, or in other words is a list with the same length as its argument. Three self-search functions follow this pattern, but Deduplicate (`⍷`) is different: it returns an array of the same rank but possibly a shorter length than the argument. ## Classify -Classify is the universal self-comparison function, in that it preserves all the self-comparison information in its argument. It gives each different cell value a natural number, ordered by first appearance. +Classify is the universal self-search function, in that it preserves all the self-search information in its argument. It gives each different cell value a natural number, ordered by first appearance. ⊐ 5‿6‿2‿2‿5‿1 @@ -60,7 +60,7 @@ Classify is the universal self-comparison function, in that it preserves all the ≍⟜⊐ 5‿6‿2‿2‿5‿1 -Applying Classify before another self-comparison function will never change the result, except in the case of Deduplicate (`⍷`), which constructs its result from cells in the argument. In particular, Classify is [idempotent](https://en.wikipedia.org/wiki/Idempotent), meaning that applying it twice is the same as applying it once. +Applying Classify before another self-search function will never change the result, except in the case of Deduplicate (`⍷`), which constructs its result from cells in the argument. In particular, Classify is [idempotent](https://en.wikipedia.org/wiki/Idempotent), meaning that applying it twice is the same as applying it once. ∊ "dbaedcbcecbcd" ∊ ⊐ "dbaedcbcecbcd" @@ -89,7 +89,7 @@ Applying both Classify and Deduplicate gives an array that has both properties ( *See the [APL Wiki page](https://aplwiki.com/wiki/Unique_Mask) on this function as well.* -Mark Firsts (`∊`) is the simplest self-comparison function: it returns `0` for any major cell of the argument that is a duplicate of an earlier cell and `1` for a major cell that's the first with its value. To implement [Deduplicate](#deduplicate) in terms of Mark Firsts, just filter out the duplicates with `∊⊸/`. +Mark Firsts (`∊`) is the simplest self-search function: it returns `0` for any major cell of the argument that is a duplicate of an earlier cell and `1` for a major cell that's the first with its value. To implement [Deduplicate](#deduplicate) in terms of Mark Firsts, just filter out the duplicates with `∊⊸/`. ∊ 3‿1‿4‿1‿5‿9‿2‿6‿5 |