From 0e4a111f81cceed275d9bec2695f6e401fb654d8 Mon Sep 17 00:00:00 2001 From: syuilo Date: Fri, 12 Nov 2021 02:02:25 +0900 Subject: refactoring Resolve #7779 --- src/prelude/array.ts | 138 --------------------------------------------------- 1 file changed, 138 deletions(-) delete mode 100644 src/prelude/array.ts (limited to 'src/prelude/array.ts') diff --git a/src/prelude/array.ts b/src/prelude/array.ts deleted file mode 100644 index d63f0475d0..0000000000 --- a/src/prelude/array.ts +++ /dev/null @@ -1,138 +0,0 @@ -import { EndoRelation, Predicate } from './relation'; - -/** - * Count the number of elements that satisfy the predicate - */ - -export function countIf(f: Predicate, xs: T[]): number { - return xs.filter(f).length; -} - -/** - * Count the number of elements that is equal to the element - */ -export function count(a: T, xs: T[]): number { - return countIf(x => x === a, xs); -} - -/** - * Concatenate an array of arrays - */ -export function concat(xss: T[][]): T[] { - return ([] as T[]).concat(...xss); -} - -/** - * Intersperse the element between the elements of the array - * @param sep The element to be interspersed - */ -export function intersperse(sep: T, xs: T[]): T[] { - return concat(xs.map(x => [sep, x])).slice(1); -} - -/** - * Returns the array of elements that is not equal to the element - */ -export function erase(a: T, xs: T[]): T[] { - return xs.filter(x => x !== a); -} - -/** - * Finds the array of all elements in the first array not contained in the second array. - * The order of result values are determined by the first array. - */ -export function difference(xs: T[], ys: T[]): T[] { - return xs.filter(x => !ys.includes(x)); -} - -/** - * Remove all but the first element from every group of equivalent elements - */ -export function unique(xs: T[]): T[] { - return [...new Set(xs)]; -} - -export function sum(xs: number[]): number { - return xs.reduce((a, b) => a + b, 0); -} - -export function maximum(xs: number[]): number { - return Math.max(...xs); -} - -/** - * Splits an array based on the equivalence relation. - * The concatenation of the result is equal to the argument. - */ -export function groupBy(f: EndoRelation, xs: T[]): T[][] { - const groups = [] as T[][]; - for (const x of xs) { - if (groups.length !== 0 && f(groups[groups.length - 1][0], x)) { - groups[groups.length - 1].push(x); - } else { - groups.push([x]); - } - } - return groups; -} - -/** - * Splits an array based on the equivalence relation induced by the function. - * The concatenation of the result is equal to the argument. - */ -export function groupOn(f: (x: T) => S, xs: T[]): T[][] { - return groupBy((a, b) => f(a) === f(b), xs); -} - -export function groupByX(collections: T[], keySelector: (x: T) => string) { - return collections.reduce((obj: Record, item: T) => { - const key = keySelector(item); - if (!obj.hasOwnProperty(key)) { - obj[key] = []; - } - - obj[key].push(item); - - return obj; - }, {}); -} - -/** - * Compare two arrays by lexicographical order - */ -export function lessThan(xs: number[], ys: number[]): boolean { - for (let i = 0; i < Math.min(xs.length, ys.length); i++) { - if (xs[i] < ys[i]) return true; - if (xs[i] > ys[i]) return false; - } - return xs.length < ys.length; -} - -/** - * Returns the longest prefix of elements that satisfy the predicate - */ -export function takeWhile(f: Predicate, xs: T[]): T[] { - const ys = []; - for (const x of xs) { - if (f(x)) { - ys.push(x); - } else { - break; - } - } - return ys; -} - -export function cumulativeSum(xs: number[]): number[] { - const ys = Array.from(xs); // deep copy - for (let i = 1; i < ys.length; i++) ys[i] += ys[i - 1]; - return ys; -} - -export function toArray(x: T | T[] | undefined): T[] { - return Array.isArray(x) ? x : x != null ? [x] : []; -} - -export function toSingle(x: T | T[] | undefined): T | undefined { - return Array.isArray(x) ? x[0] : x; -} -- cgit v1.2.3-freya