如何从数组中删除特定项目? [英] How can I remove a specific item from an array?

问题描述

我有一个数字数组，我正在使用 .push() 方法向其中添加元素.

I have an array of numbers and I'm using the .push() method to add elements to it.

是否有一种简单的方法可以从数组中删除特定元素?

Is there a simple way to remove a specific element from an array?

我正在寻找类似的东西:

I'm looking for the equivalent of something like:

array.remove(number);

我必须使用核心 JavaScript.不允许使用框架.

I have to use core JavaScript. Frameworks are not allowed.

推荐答案

使用 indexOf，然后使用 splice.

Find the index of the array element you want to remove using indexOf, and then remove that index with splice.

splice() 方法通过删除现有元素和/或添加新元素.

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

const array = [2, 5, 9];

console.log(array);

const index = array.indexOf(5);
if (index > -1) {
  array.splice(index, 1);
}

// array = [2, 9]
console.log(array); 

splice 的第二个参数是要移除的元素数量.请注意，splice 修改了数组并返回一个包含已删除元素的新数组.

The second parameter of splice is the number of elements to remove. Note that splice modifies the array in place and returns a new array containing the elements that have been removed.

为了完整起见，这里是函数.第一个函数只删除一个匹配项(即从 [2,5,9,1,5,8,5] 中删除 5 的第一个匹配项)，而第二个函数删除所有出现的:

For the reason of completeness, here are functions. The first function removes only a single occurrence (i.e. removing the first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:

function removeItemOnce(arr, value) {
  var index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

function removeItemAll(arr, value) {
  var i = 0;
  while (i < arr.length) {
    if (arr[i] === value) {
      arr.splice(i, 1);
    } else {
      ++i;
    }
  }
  return arr;
}
// Usage
console.log(removeItemOnce([2,5,9,1,5,8,5], 5))
console.log(removeItemAll([2,5,9,1,5,8,5], 5))

在 TypeScript 中，这些函数可以通过类型参数保持类型安全:

In TypeScript, these functions can stay type-safe with a type parameter:

function removeItem<T>(arr: Array<T>, value: T): Array<T> { 
  const index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  }
  return arr;
}

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