Array.splice 没有返回正确的输出答案

【问题标题】：Array.splice is not returning the correct outputArray.splice 没有返回正确的输出
【发布时间】：2017-10-01 12:05:58
【问题描述】：

如果两个数组包含相同的值，我会尝试匹配它们，它将从数组之一中删除元素。我尝试使用splice() 方法。我尝试阅读但输出是：

new array ["SUGAR"]

但是，我想实现这个输出：

["HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"]

这是原始数组 (unSafe)：

["SUGAR", "HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"]

这是我的代码：

function breakArray() {
  let warning = this.navParams.get("warningResult");
  let unSafe = this.navParams.get("unSafeResult");

  console.log(unSafe);
  console.log(warning);

  for (var i = 0; i < warning.length; i++) {
    for (var j = 0; j < unSafe.length; j++) {
      if (warning[i] === unSafe[j]) {
        console.log('warning', i);
        console.log('unSafe', j);

        unSafe.splice(j, 1);

        console.log('new array', unSafe);
      }
    }
  }
}

【问题讨论】：

标签： javascript arrays typescript ionic2

【解决方案1】：

您需要确保 j 为 0。

// Original array.
var unsafe = ["SUGAR", "HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"];

// Find the index of the item.
let removeIndexStart = unsafe.indexOf('SUGAR');

// Check if it exists.
if (removeIndexStart > -1) {
  // Returns the removed items (from index 0, removing 1 item)
  // and modifies the array in-place.
  var removed = unsafe.splice(removeIndexStart, 1);

  console.log('Removed:', JSON.stringify(removed, null, 2));
}

console.log('Modified:', JSON.stringify(unsafe, null, 2));

.as-console-wrapper { top: 0; max-height: 100% !important; }

尝试反向工作：

for (var i = warning.length - 1; i >= 0; i--) {

并在更大的数组上进行操作，这正是您想要的。

warning.splice(i, 1);

let warning = ["SUGAR", "HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"];
let unSafe =  ["SUGAR"];

breakArray(); // I would pass in arguments.

console.log('New array:', warning);

function breakArray() {
  for (var i = warning.length - 1; i >= 0; i--) {
    for (var j = 0; j < unSafe.length; j++) {
      if (warning[i] === unSafe[j]) {
        console.log('warning', i);
        console.log('unSafe', j);

        warning.splice(i, 1);
      }
    }
  }
}

.as-console-wrapper { top: 0; max-height: 100% !important; }

【讨论】：

您好，它正在工作。如console.log 显示0：“氢化蔬菜↵油”1：“油菜籽油”2：“棕榈油”3：“葵花籽油”4：“油菜籽油”5：“棕榈油”谢谢您的帮助跨度>

【解决方案2】：

使用filter 方法代替splice 方法。你不想拼接你正在迭代的数组。

let unsafeArray = ["SUGAR", "HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"];

let warningArray = ["SUGAR", "SUNFLOWER OIL"];

let filteredArray = unsafeArray;

warningArray.forEach(function (warningElement) {
  filteredArray = filteredArray.filter(function (unsafeElement) {
    return unsafeElement !== warningElement;
  });
});

console.log(filteredArray);

【讨论】：

向后搜索总是可以拼接的。
可以，但过滤器更简单 IMO

【解决方案3】：

似乎工作正常。返回没有“警告”元素的数组。

function breakArray() {
  //let warning = this.navParams.get("warningResult");
  //let unSafe = this.navParams.get("unSafeResult");
  var warning = ["SUGAR"];
  var unSafe = ["SUGAR", "HYDROGENATED VEGETABLE↵OIL", "RAPESEED OIL", "PALM OIL", "SUNFLOWER OIL", "RAPESEED OIL", "PALM OIL"];

  //console.log(unSafe);
  //console.log(warning);

  for (var i = 0; i < warning.length; i++) {
    for (var j = 0; j < unSafe.length; j++) {
      if (warning[i] === unSafe[j]) {
        //console.log('warning', i);
        //console.log('unSafe', j);

        unSafe.splice(j, 1);

        console.log('new array', unSafe);
      }
    }
  }
}

breakArray();

【讨论】：