getURLParameters
0 likes • Nov 19, 2022
JavaScript
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const gcd = (...arr) => {const _gcd = (x, y) => (!y ? x : gcd(y, x % y));return [...arr].reduce((a, b) => _gcd(a, b));};gcd(8, 36); // 4gcd(...[12, 8, 32]); // 4
const euclideanDistance = (a, b) =>Math.hypot(...Object.keys(a).map(k => b[k] - a[k]));euclideanDistance([1, 1], [2, 3]); // ~2.2361euclideanDistance([1, 1, 1], [2, 3, 2]); // ~2.4495
class Timer{start(){this.startTime = Date.now();}stop(){const dt = Date.now() - this.startTime;console.log(dt);return dt;}getExecTime(fun, asynchronous){return asynchronous ? this.getAsyncExecTime(fun) : this.getSyncExecTime(fun);}getSyncExecTime(fun){this.start();fun();return this.stop();}async getAsyncExecTime(fun){this.start();await fun();return this.stop();}static average(fun, numTimes, asynchronous = false){const times = [];const promises = [];let timer = new Timer();if(asynchronous){for(let i = 0; i < numTimes; i++){timer.getAsyncExecTime(fun);}}else{for(let i = 0; i < numTimes; i++){timer.getSyncExecTime(fun);}}return (times => times.reduce(((sum, acc) => sume + acc), 0) / times.length);}static async timeAsync(fun, numTimes){if(numTimes <= 1) return new Timer().getAsyncExecTime(fun);const promises = [];let timer = new Timer(true);for(let i = 0; i < numTimes; i++){promises.push(fun().catch((e)=>{}));}try{await Promise.all(promises).catch((e)=>{});}catch(e){//do absolutely nothing}return timer.stop();}constructor(start = false){if(start) this.start();}}
if (process.env.NODE_ENV === "production") {app.use(express.static("client/build"));app.get("*", (req, res) => {res.sendFile(path.resolve(__dirname, "client", "build", "index.html"));});}
import React, { useState } from 'react' import Welcome from '../components/Welcome' function About() { const [showWelcome, setShowWelcome] = useState(false) return ( <div> {showWelcome ? <Welcome /> : null} </div> <div> {showWelcome && <Welcome /> } </div> ) } export default App
const kNearestNeighbors = (data, labels, point, k = 3) => {const kNearest = data.map((el, i) => ({dist: Math.hypot(...Object.keys(el).map(key => point[key] - el[key])),label: labels[i]})).sort((a, b) => a.dist - b.dist).slice(0, k);return kNearest.reduce((acc, { label }, i) => {acc.classCounts[label] =Object.keys(acc.classCounts).indexOf(label) !== -1? acc.classCounts[label] + 1: 1;if (acc.classCounts[label] > acc.topClassCount) {acc.topClassCount = acc.classCounts[label];acc.topClass = label;}return acc;},{classCounts: {},topClass: kNearest[0].label,topClassCount: 0}).topClass;};const data = [[0, 0], [0, 1], [1, 3], [2, 0]];const labels = [0, 1, 1, 0];kNearestNeighbors(data, labels, [1, 2], 2); // 1kNearestNeighbors(data, labels, [1, 0], 2); // 0