Question

我正在尝试在数组上执行for循环，并能够在特定索引上启动该循环，并在数组上循环x次。

const array = ['c','d','e','f','g','a','b','c']

我想循环8个从我希望的任何索引开始的索引。从array [4]（g）开始的示例将返回

'g','a','b','c','c','d','e','f'

这是我到目前为止尝试过的

const notes = ['c','d','e','f','g','a','b','c']

var res = []
for (var i = 4; i < notes.length; i++) {
res.push(notes[i])
}

console.log(res)

Answer 1

您可以使用％模运算符。

    const getArray = (array, index) => {
      const result = [];
      const length = array.length;
      for (let i = 0; i < length; i++) {
        result.push(array[(index + i) % length]);
      }
      return result;
    };

Answer 2

简单方法。

var notes = ['c','d','e','f','g','a','b','c'];

function looparr(arr, start)
{
    var res = [], start = start || 0;
    for(var index = start, length=arr.length; index<length; index++)
    {
        res.push(arr[index]);
        index == (arr.length-1) && (index=-1,length=start);
    }
    return res;
}

console.log(looparr(['c','d','e','f','g','a','b','c'], 0));
console.log(looparr(['c','d','e','f','g','a','b','c'], 2));
console.log(looparr(['c','d','e','f','g','a','b','c'], 4));
console.log(looparr(['c','d','e','f','g','a','b','c']));

Answer 3

以下非常简单的解决方案：）当i

let array = ['c','d','e','f','g','a','b','c'];
var index = 4;

    for(var i = 0; i < index; i++){
        var letter1 = array.shift(i); // Remove from the start of the array
        array.push(letter1); // Add the value to the end of the array
    }
    console.log(array);

享受：）

在特定索引上启动for循环并循环获取数组长度

3 个答案: