如何从数组中删除一个特定值? 类似 :
array.remove(value);
制约:我必须使用核心 JavaScript 。 框架不允许 。
如何从数组中删除一个特定值? 类似 :
array.remove(value);
制约:我必须使用核心 JavaScript 。 框架不允许 。
当前回答
使用 JavaScript 原型特性定义列对象上名为删除() 的方法 。
使用 spolice () 方法满足您的要求 。
请看看下面的代码
Array.prototype.remove = function(item) {
// 'index' will have -1 if 'item' does not exist,
// else it will have the index of the first item found in the array
var index = this.indexOf(item);
if (index > -1) {
// The splice() method is used to add/remove items(s) in the array
this.splice(index, 1);
}
return index;
}
var arr = [ 11, 22, 67, 45, 61, 89, 34, 12, 7, 8, 3, -1, -4];
// Printing array
// [ 11, 22, 67, 45, 61, 89, 34, 12, 7, 8, 3, -1, -4];
console.log(arr)
// Removing 67 (getting its index, i.e. 2)
console.log("Removing 67")
var index = arr.remove(67)
if (index > 0){
console.log("Item 67 found at ", index)
} else {
console.log("Item 67 does not exist in array")
}
// Printing updated array
// [ 11, 22, 45, 61, 89, 34, 12, 7, 8, 3, -1, -4];
console.log(arr)
// ............... Output ................................
// [ 11, 22, 67, 45, 61, 89, 34, 12, 7, 8, 3, -1, -4 ]
// Removing 67
// Item 67 found at 2
// [ 11, 22, 45, 61, 89, 34, 12, 7, 8, 3, -1, -4 ]
注:以下是Norde.js REPL上执行的完整示例代码,该代码描述推()、流行()、转移()、非轮档()和交点()方法的使用。
> // Defining an array
undefined
> var arr = [12, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34];
undefined
> // Getting length of array
undefined
> arr.length;
16
> // Adding 1 more item at the end i.e. pushing an item
undefined
> arr.push(55);
17
> arr
[ 12, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34, 55 ]
> // Popping item from array (i.e. from end)
undefined
> arr.pop()
55
> arr
[ 12, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
> // Remove item from beginning
undefined
> arr.shift()
12
> arr
[ 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
> // Add item(s) at beginning
undefined
> arr.unshift(67); // Add 67 at beginning of the array and return number of items in updated/new array
16
> arr
[ 67, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
> arr.unshift(11, 22); // Adding 2 more items at the beginning of array
18
> arr
[ 11, 22, 67, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
>
> // Define a method on array (temporarily) to remove an item and return the index of removed item; if it is found else return -1
undefined
> Array.prototype.remove = function(item) {
... var index = this.indexOf(item);
... if (index > -1) {
..... this.splice(index, 1); // splice() method is used to add/remove items in array
..... }
... return index;
... }
[Function]
>
> arr
[ 11, 22, 67, 45, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
>
> arr.remove(45); // Remove 45 (you will get the index of removed item)
3
> arr
[ 11, 22, 67, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
>
> arr.remove(22) // Remove 22
1
> arr
[ 11, 67, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
> arr.remove(67) // Remove 67
1
> arr
[ 11, 67, 89, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
>
> arr.remove(89) // Remove 89
2
> arr
[ 11, 67, 34, 12, 7, 8, 3, -1, -4, -11, 0, 56, 12, 34 ]
>
> arr.remove(100); // 100 doesn't exist, remove() will return -1
-1
>
其他回答
(function removeFromArrayPolyfill() {
if (window.Array.prototype.remove) return;
Array.prototype.remove = function (value) {
if (!this.length || !value) return;
const indexOfValue = this.indexOf(value);
if (indexOfValue >= 0) {
this.splice(indexOfValue, 1);
}
};
})();
// testing polyfill
const nums = [10, 20, 30];
nums.remove(20);
console.log(nums);//[10,30]
根据索引删除
函数返回在索引中没有元素的数组副本 :
/**
* removeByIndex
* @param {Array} array
* @param {Number} index
*/
function removeByIndex(array, index){
return array.filter(function(elem, _index){
return index != _index;
});
}
l = [1,3,4,5,6,7];
console.log(removeByIndex(l, 1));
$> [ 1, 4, 5, 6, 7 ]
以值删除
函数返回没有值的数组副本。
/**
* removeByValue
* @param {Array} array
* @param {Number} value
*/
function removeByValue(array, value){
return array.filter(function(elem, _index){
return value != elem;
});
}
l = [1,3,4,5,6,7];
console.log(removeByValue(l, 5));
$> [ 1, 3, 4, 6, 7]
对于任何想要复制一种方法的人,如果想复制一种方法,返回一个重复删除数字或字符串的新阵列,则从现有答案中归纳如下:
function uniq(array) {
var len = array.length;
var dupFree = [];
var tempObj = {};
for (var i = 0; i < len; i++) {
tempObj[array[i]] = 0;
}
console.log(tempObj);
for (var i in tempObj) {
var element = i;
if (i.match(/\d/)) {
element = Number(i);
}
dupFree.push(element);
}
return dupFree;
}
正在删除带有索引和相交点的值 !
function removeArrValue(arr,value) {
var index = arr.indexOf(value);
if (index > -1) {
arr.splice(index, 1);
}
return arr;
}
一个非常天真的执行情况如下:
Array. prototype. remove = 函数( data) { const dataIdx = this. indexof( data) if (dataIdx { { { 0) { this.spice( dataIdx, 1) { 返回此. 长度;} } 允许 a = [1, 2,3] ; / / 这将将 Arr a 改为 [1, 3] a. remove(2) ;
我从函数返回数组的长度以遵守其他方法, 如 Array. prototype. push () 。