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

我会这样编码:

function range(start, end) {
    return Array(end-start).join(0).split(0).map(function(val, id) {return id+start});
}  

range(-4,2);
// [-4,-3,-2,-1,0,1]

range(3,9);
// [3,4,5,6,7,8]

它的行为类似于Python范围:

>>> range(-4,2)
[-4, -3, -2, -1, 0, 1]

其他回答

对一些不同的范围函数进行了研究。检查执行这些函数的不同方法的jsperf比较。当然不是一个完美或详尽的列表,但应该有帮助:)

获胜者是。。。

function range(lowEnd,highEnd){
    var arr = [],
    c = highEnd - lowEnd + 1;
    while ( c-- ) {
        arr[c] = highEnd--
    }
    return arr;
}
range(0,31);

从技术上讲,它不是firefox上最快的,但铬合金上的疯狂速度差(imho)弥补了这一点。

还有一个有趣的观察是,与firefox相比,chrome使用这些阵列功能的速度要快得多。Chrome速度至少快4或5倍。

(from, to) => [...Array(to - from)].map((_,i)=> i + from)
/**
 * @param {!number|[!number,!number]} sizeOrRange Can be the `size` of the range (1st signature) or a
 *   `[from, to]`-shape array (2nd signature) that represents a pair of the *starting point (inclusive)* and the
 *   *ending point (exclusive)* of the range (*mathematically, a left-closed/right-open interval: `[from, to)`*).
 * @param {!number} [fromOrStep] 1st signature: `[from=0]`. 2nd signature: `[step=1]`
 * @param {!number} [stepOrNothing] 1st signature: `[step=1]`. 2nd signature: NOT-BEING-USED
 * @example
 * range(5) ==> [0, 1, 2, 3, 4] // size: 5
 * range(4, 5)    ==> [5, 6, 7, 8]  // size: 4, starting from: 5
 * range(4, 5, 2) ==> [5, 7, 9, 11] // size: 4, starting from: 5, step: 2
 * range([2, 5]) ==> [2, 3, 4] // [2, 5) // from: 2 (inclusive), to: 5 (exclusive)
 * range([1, 6], 2) ==> [1, 3, 5] // from: 1, to: 6, step: 2
 * range([1, 7], 2) ==> [1, 3, 5] // from: 1, to: 7 (exclusive), step: 2
 * @see {@link https://stackoverflow.com/a/72388871/5318303}
 */
export function range (sizeOrRange, fromOrStep, stepOrNothing) {
  let from, to, step, size
  if (sizeOrRange instanceof Array) { // 2nd signature: `range([from, to], step)`
    [from, to] = sizeOrRange
    step = fromOrStep ?? 1
    size = Math.ceil((to - from) / step)
  } else { // 1st signature: `range(size, from, step)`
    size = sizeOrRange
    from = fromOrStep ?? 0
    step = stepOrNothing ?? 1
  }
  return Array.from({length: size}, (_, i) => from + i * step)
}

示例:

控制台日志(范围(5),//[0,1,2,3,4]//size:5范围([2,5]),//[2,3,4]//[2、5)//从:2(含)到:5(不含)范围(4,2),//[2,3,4,5]//大小:4,从:2开始范围([1,6],2),//[1,3,5]//从:1到:6,步骤:2范围([1,7],2),//[1,3,5]//从:1到:7(不含),步骤:2)<脚本>函数范围(sizeOrRange、fromOrStep、stepOrNothing){让从、到、步长、大小if(sizeOrRange instanceof Array){//第二个签名:`range([from,to],step)`[from,to]=sizeOrRange步骤=来自或步骤??1.size=数学ceil((to-from)/步长)}else{//第一个签名:`range(大小,从,步)`size=sizeOrRangefrom=来自或步骤??0step=stepOrNothing??1.}return Array.from({length:size},(_,i)=>from+i*step)}</script>

这是我的2美分:

function range(start, end) {
  return Array.apply(0, Array(end - 1))
    .map((element, index) => index + start);
}

我喜欢下面的路

var范围=函数(x,y){return数组(y-x+1).fill(x).map((a,b)=>{return a+b}).filter(i=>i>=x);};console.log(范围(3,10));