Javascript - 动态从数组中获取元素

Posted 2023-05-08

【中文标题】Javascript - 动态从数组中获取元素

【英文标题】：Javascript - fetch elements from array dynamically

【发布时间】：2017-02-22 23:11:57

【问题描述】：

我有一个数组，我需要从循环内的数组中获取元素。让我解释一下，

var globalArray = ['apple','orange','melon','banana'],
    loopLimit = 5,
    fruitsPerLoop = 3;

for (var i=1; i<=loopLimit; i++) 
   // when the loop runs for the first time i need to grab the first 3 elements from the array since fruitsPerLoop is 3 and for the second time the next 3 (out of bound should be taken care) and for third time etc...
   //Pseudo with fruitsPerLoop as 3
   when i = 1 ==> globalArray should be ['apple','orange','melon'] 
        i = 2 ==> globalArray should be ['banana', 'apple','orange']
        i = 3 ==> globalArray should be ['melon','banana', 'apple']
        i = 4 ==> globalArray should be ['orange','melon','banana']
        i = 5 ==> globalArray should be ['apple','orange','melon']

我指的是 underscore.js 并尝试使用一些本机方法，但它在某些时候会中断。

【问题讨论】：

所以你想旋转阵列？见***.com/questions/1985260/javascript-array-rotate

嗯 loopLimit 是一个数字，那为什么是 loopLimit.length？不应该只是loopLimit吗？

@Unicode 你是对的，已编辑

【参考方案1】：

如何创建一个递归函数来确定索引：-

var globalArray = ['apple', 'orange', 'melon', 'banana'],
  loopLimit = 5,
  fruitsPerLoop = 3;

function getIndex(i, minus) 
  var index = i - minus;
  if (index < 0)
    return getIndex(globalArray.length, minus - i)
  return globalArray[index];


for (var i = 1; i <= loopLimit; i++) 
  console.log([getIndex(1, i), getIndex(2, i), getIndex(3, i)])