31:[] 2f:{"title":"Factor Functions","cells":[{"id":0,"value":"md`# Factor Functions\n\nThis is a work in progress. The functions are designed to work with integers.\n\n~~~js\nimport { factorLib } from \"@harrystevens/factor-functions@509\"\n~~~`","pinned":false,"hidden":false,"mode":"ojs"},{"id":99,"value":"factorLib = ({ factors, gcd, lcm, pairs, prime, primes, square, squares });","pinned":false,"hidden":false,"mode":"ojs"},{"id":267,"value":"md`factors(integer)\n\nReturns an array containing the factors of an integer.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":255,"value":"factors = n => {\n const result = [];\n for (let i = 0, l = n; i <= l; i++){\n if (n % i === 0) result.push(i);\n }\n return result;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":73,"value":"md`gcd(a, b)\n\nReturns the greatest common divisor of two integers a and b.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":62,"value":"function gcd(a, b) {\n if (!b) return a;\n return gcd(b, a % b);\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":341,"value":"md`lcm(a, b)\n\nReturns the greatest least common multiple of two integers a and b.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":337,"value":"function lcm(a, b) {\n return a * b / gcd(a, b)\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":157,"value":"md`pairs(integer)\n\nReturns an array containing the pairs of integers whose product is an integer.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":137,"value":"pairs = n => {\n const neg = n < 0;\n if (neg) n *= -1;\n \n const pairs = [];\n const fs = factors(n);\n for (let i = 0, l = fs.length; i < l; i++){\n const factor = fs[i];\n const pair = n / factor;\n \n if (neg) {\n pairs.push([factor * (neg ? -1 : 1), pair]);\n }\n else {\n if (pairs.map(d => d[1]).includes(factor)){\n break;\n }\n else {\n pairs.push([factor, pair], [-factor, -pair]);\n }\n }\n }\n return pairs;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":29,"value":"md`prime(number)\n\nReturns a boolean representing whether a number is prime.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":5,"value":"function prime(n) {\n if (!Number.isInteger(n) || n === 1) { return false; }\n for (let i = 2; i <= Math.sqrt(n); i++) {\n if (n % i === 0) return false;\n }\n return true;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":22,"value":"md`primes(number)\n\nReturns an array containing the prime factors of a number.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":2,"value":"function primes(n){\n const result = [];\n if (!Number.isInteger(n)) { return result; }\n for (let i = 2; i <= n; i++) {\n while (prime(i) && n % i === 0) {\n if (!result.includes(i)) result.push(i);\n n /= i;\n }\n }\n return result;\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":503,"value":"md`square(number)\n\nReturns a boolean representing whether a number is a perfect square.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":473,"value":"function square(n){\n return Number.isInteger(Math.sqrt(n));\n}","pinned":true,"hidden":false,"mode":"ojs"},{"id":506,"value":"md`squares(number)\n\nReturns an array containing the perfect square factors of a number.`","pinned":false,"hidden":false,"mode":"ojs"},{"id":484,"value":"function squares(n){\n const result = [];\n if (!Number.isInteger(n)) { return result; }\n for (let i = 0, l = n; i <= l; i++){\n if (n % i === 0 && square(i)) result.push(i);\n }\n return result;\n}","pinned":true,"hidden":false,"mode":"ojs"}],"files":"$W31","stdlib":"1","titling":"auto"}