JavaScript 有没有像“range()"这样的方法?在提供的范围内生成一个范围?

问题描述

在 PHP 中，你可以做...

In PHP, you can do...

range(1, 3); // Array(1, 2, 3)
range("A", "C"); // Array("A", "B", "C")

也就是说，有一个函数可以让你通过传递上下限来得到一个数字或字符的范围.

That is, there is a function that lets you get a range of numbers or characters by passing the upper and lower bounds.

JavaScript 是否有为此内置任何内容?如果没有，我将如何实施?

Is there anything built-in to JavaScript natively for this? If not, how would I implement it?

推荐答案

数字

[...Array(5).keys()];
 => [0, 1, 2, 3, 4]

字符迭代

String.fromCharCode(...[...Array('D'.charCodeAt(0) - 'A'.charCodeAt(0) + 1).keys()].map(i => i + 'A'.charCodeAt(0)));
 => "ABCD"

迭代

for (const x of Array(5).keys()) {
  console.log(x, String.fromCharCode('A'.charCodeAt(0) + x));
}
 => 0,"A" 1,"B" 2,"C" 3,"D" 4,"E"

作为函数

function range(size, startAt = 0) {
    return [...Array(size).keys()].map(i => i + startAt);
}

function characterRange(startChar, endChar) {
    return String.fromCharCode(...range(endChar.charCodeAt(0) -
            startChar.charCodeAt(0), startChar.charCodeAt(0)))
}

类型化函数

function range(size:number, startAt:number = 0):ReadonlyArray<number> {
    return [...Array(size).keys()].map(i => i + startAt);
}

function characterRange(startChar:string, endChar:string):ReadonlyArray<string> {
    return String.fromCharCode(...range(endChar.charCodeAt(0) -
            startChar.charCodeAt(0), startChar.charCodeAt(0)))
}

lodash.js _.range() 函数

lodash.js _.range() function

_.range(10);
 => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
_.range(1, 11);
 => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
_.range(0, 30, 5);
 => [0, 5, 10, 15, 20, 25]
_.range(0, -10, -1);
 => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]
String.fromCharCode(..._.range('A'.charCodeAt(0), 'D'.charCodeAt(0) + 1));
 => "ABCD"

没有库的旧非 es6 浏览器:

Old non es6 browsers without a library:

Array.apply(null, Array(5)).map(function (_, i) {return i;});
 => [0, 1, 2, 3, 4]

console.log([...Array(5).keys()]);

(ES6 归功于 nils petersohn 和其他评论者)

这篇关于JavaScript 有没有像“range()"这样的方法?在提供的范围内生成一个范围?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！