在PHP中,您可以。。。

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

也就是说,有一个函数可以通过传递上下限来获得一系列数字或字符。

JavaScript本机是否有内置的功能?如果没有,我将如何实施?


当前回答

使用TypeScript设置(应用程序范围):

declare global {
  interface Function {
    range(count: number, start_with: number): number[];
  }
}

Function.prototype.range = function (
  count: number,
  start_with: number = 0
): number[] {
  return [...Array(count).keys()].map((key) => key + start_with);
};

使用JS设置:

Function.prototype.range = function(count, start_with=0){
    return [...Array(count).keys()].map((key) => key + start_with);
}

使用示例:

Function.range(2,0) //Will return [0,1]
Function.range(2,1) //Will return [1,2]
Function.range(2,-1) //Will return [-1,0]

其他回答

Array.from(Array((m - n + 1)), (v, i) => n + i); // m > n and both of them are integers.

ES6

使用Array.from(此处为文档):

const range = (start, stop, step) => Array.from({ length: (stop - start) / step + 1}, (_, i) => start + (i * step));

这是我模仿Python的解决方案。在底部,您可以找到一些如何使用它的示例。它与数字一起工作,就像Python的范围一样:

var assert = require('assert');    // if you use Node, otherwise remove the asserts

var L = {};    // L, i.e. 'list'

// range(start, end, step)
L.range = function (a, b, c) {
    assert(arguments.length >= 1 && arguments.length <= 3);
    if (arguments.length === 3) {
        assert(c != 0);
    }

    var li = [],
        i,
        start, end, step,
        up = true;    // Increasing or decreasing order? Default: increasing.

    if (arguments.length === 1) {
        start = 0;
        end = a;
        step = 1;
    }

    if (arguments.length === 2) {
        start = a;
        end = b;
        step = 1;
    }

    if (arguments.length === 3) {
        start = a;
        end = b;
        step = c;
        if (c < 0) {
            up = false;
        }
    }

    if (up) {
        for (i = start; i < end; i += step) {
            li.push(i);
        }
    } else {
        for (i = start; i > end; i += step) {
            li.push(i);
        }
    }

    return li;
}

示例:

// range
L.range(0) -> []
L.range(1) -> [0]
L.range(2) -> [0, 1]
L.range(5) -> [0, 1, 2, 3, 4]

L.range(1, 5) -> [1, 2, 3, 4]
L.range(6, 4) -> []
L.range(-2, 2) -> [-2, -1, 0, 1]

L.range(1, 5, 1) -> [1, 2, 3, 4]
L.range(0, 10, 2) -> [0, 2, 4, 6, 8]
L.range(10, 2, -1) -> [10, 9, 8, 7, 6, 5, 4, 3]
L.range(10, 2, -2) -> [10, 8, 6, 4]
Array.range = function(a, b, step){
    var A = [];
    if(typeof a == 'number'){
        A[0] = a;
        step = step || 1;
        while(a+step <= b){
            A[A.length]= a+= step;
        }
    }
    else {
        var s = 'abcdefghijklmnopqrstuvwxyz';
        if(a === a.toUpperCase()){
            b = b.toUpperCase();
            s = s.toUpperCase();
        }
        s = s.substring(s.indexOf(a), s.indexOf(b)+ 1);
        A = s.split('');        
    }
    return A;
}
    
    
Array.range(0,10);
// [0,1,2,3,4,5,6,7,8,9,10]
    
Array.range(-100,100,20);
// [-100,-80,-60,-40,-20,0,20,40,60,80,100]
    
Array.range('A','F');
// ['A','B','C','D','E','F')
    
Array.range('m','r');
// ['m','n','o','p','q','r']

我正在分享我的实现,以防它对某人有所帮助。

function Range(start_or_num, end = null, increment = 1) {
    const end_check = end === null
    const start = end_check  ? 0 : start_or_num
    const count = end_check ? start_or_num : Math.round((end - start) / increment) + 1
     const filterFunc = end_check  ?  x => x >= start : x => x < end && x >= start

    return [...Array.from(
        Array(count).keys(), x => increment * (x - 1) + start
    )
    ].filter(filterFunc)
}
// usage
// console.log(Range(4, 10, 2)) // [4, 6, 8]
// console.log(Range(5, 10 )) //[5, 6, 7, 8, 9]
// console.log(Range(10 ))// [0, 1, 2, 3, 4, 5, 6, 7, 8]