15. 计算字符串中特定字符的出现次数 countOccurrences函数接受两个参数,一个是字符串,另一个是要计算的字符,然后返回该字符在字符串中出现的次数。 function countOccurrences(str, target) { return str.split(target).length - 1; } 16. 随机生成指定范围内的整数 有时,你可能需要生成指定范围内的整数,而不...
// 更简单的方式,使用String.prototype.match function countOccurrences(regex, str) { if (!regex.global) { throw new Error('Please set flag /g of regex'); } return (str.match(regex) || []).length; } 四十一、引用文本 给制定的字符串拼装成正则表达式,所有特殊是字符都需要进行转义。 function...
y: 0 }; // Two numeric properties let p2 = { x: point.x, y: point.y+1 }; // More complex values let book = { "main title": "JavaScript", // These property names include spaces, "sub-title": "The Definitive Guide", // and hyphens, so use string literals. for...
Imagine we want to find a specific name in a text file and count its occurrences. How will we be doing that in our command prompt? The command looks like this:cat jsBook | grep –i "composing" | wc这个命令通过组合许多函数解决了我们的问题。编写不仅仅是 UNIX/LINUX 命令行独有的;它是函...
const countOccurrences = (arr, value) => arr.reduce((a, v) => v === value ? a + 1 : a + 0, 0);// countOccurrences([1,1,2,1,2,3], 1) -> 3 当前URL 使用 window.location.href 来获取当前 URL。const currentUrl = _ => window.location.href;// currentUrl() -> 'https:...
{"main title":"JavaScript",// These property names include spaces,"sub-title":"The Definitive Guide",// and hyphens, so use string literals.for:"all audiences",// for is reserved, but no quotes.author: {// The value of this property isfirstname:"David",// itself an object.surname:...
console.log(countOccurrences([ 1, 3, 3, 4, 3, 3, 2, 3], 3)); // 5 9. capitalizeWord 此代码片段将给定字符串中每个单词的首字母转为大写。 const capitalizeWord = (string) => string.replace(/\b[a-z]/g, (char) => char.toUpperCase()); ...
constcountOccurrences =(arr, val) =>arr.reduce((a, v) =>(v === val ? a +1: a),0);countOccurrences([2,4,6,2,5,2],2)// 3countOccurrences([1,4,6,2,5,6],6)// 2 7、字谜 此片段代码用于检查特定字符...
但是在Object.prototype上定义的这两个方法往往不能满足我们的需求(Object.prototype.valueOf()仅仅返回对象本身),因此js的许多内置对象都重写了这两个函数,以实现更适合自身的功能需要(比如说,String.prototype.valueOf就覆盖了在Object.prototype中定义的valueOf)。当我们自定义对象的时候,最好也重写这个方法。重写...
countOccurrences([2,4,6,2,5,2], 2) // 3 countOccurrences([1,4,6,2,5,6], 6) // 2 7、字谜 此片段代码用于检查特定字符串是否为字谜。字谜是可以改写成另一个词的词。 const Anagram = (string1, string2) => { const normalize = str =>str ...