Question

我有一个N元素的数组。我想分成两个阵列。唯一的条件是第一个新数组由原始数组的前三个元素组成，第二个新数组必须包含所有其他元素。例如，原始数组包含["a","b","c","d","e","f","g","h"]。我想创建两个新阵列：

first new array: ["a, "b", "c"];
second new array: ["d","e","f", "g","h"].

但是我的代码将原始数组划分了很多时间。为什么呢？

＆＃13;

function MyCtrl($scope) {
$scope.strengthChartData = ["Banana", "Orange", "Apple", "Mango", "asd", "lol", "ahhhaha", "llllll", "ehhehehe", "oooo", "aaaaa", "bbbbbbbb"];

$scope.arrays = [];
var size = 3;

while ($scope.strengthChartData.length > 0)
    $scope.arrays.push($scope.strengthChartData.splice(0, size));
}

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app ng-controller="MyCtrl">
    <h3>All elements:</h3>
    <br>
    <ul>
        <li ng-repeat="array in arrays">{{array}}</li>
    </ul>
    
    <h3>First array:</h3>
    <br>
    <ul>
        <li ng-repeat="array in arrays[0]">{{array}}</li>
    </ul>

    <h3>Second array:</h3>
    <br>
    <ul>
        <li ng-repeat="array in arrays[1]">{{array}}</li>
    </ul>
</div>

＆＃13;

Answer 1

您可以使用 splice()

＆＃13;

var arr = ["a", "b", "c", "d", "e", "f", "g", "h"],
  arr1 = arr.splice(3);

document.write(JSON.stringify(arr) + '<br/>' + JSON.stringify(arr1));

＆＃13;

更新：如果您不想更新原始数组，那么创建新数组并应用 splice() 或使用 slice()

仅使用 slice()

＆＃13;

var arr = ["a", "b", "c", "d", "e", "f", "g", "h"],
  arr1 = arr.slice(0, 3);
arr2 = arr1.slice(3);

document.write(JSON.stringify(arr) + '<br/>' +
  JSON.stringify(arr1) + '<br/>' +
  JSON.stringify(arr2));

＆＃13;

使用 splice() 和 slice() ，不带任何参数来复制所有元素

＆＃13;

var arr = ["a", "b", "c", "d", "e", "f", "g", "h"],
  arr1 = arr.slice();
arr2 = arr1.splice(3);

document.write(JSON.stringify(arr) + '<br/>' +
  JSON.stringify(arr1) + '<br/>' +
  JSON.stringify(arr2));

＆＃13;

Answer 2

var a = ["a","b","c","d","e","f","g","h"];

var b = a.slice(0,3); // => ["a","b","c"]
var c = a.slice(3);   // => ["d", "e", ... ]

Answer 3

使用切片，例如：

mvn -Dstage=local process-resources

Answer 4

至于原因：

strengthChartData的长度为12.在您的同时，您正在推送arrays变量3 strengthChartData的第一个元素，并且您要将其从strengthChartData中删除，因为splice修改了数组。

所以你的长度现在是3减去。当长度大于0时，你正在执行此操作，这意味着它将在长度为12,9,6,3时运行并且将在0处停止。因此，您实际上是从strengthChartData推送前3个元素的四倍到array变量

在Javascript中将数组分为两部分

4 个答案: