从数组中删除/弹出元素

Question

I know this could be quite simple for someone else but I can't think of any solution.

I have an array called breadcrumb with the following elements breadcrumb = [a, b, c, d]

I also know the index of b. How do I pop all other elements from the array after index of b in JavaScript. the final array should look like this

breadcrumb = [a, b]

Answer 1

There's the slice method in the Array prototype :

var breadcrumb = ['a', 'b', 'c', 'd'];
// in case you have to find the index of the element
var index = breadcrumb.indexOf('b');
breadcrumb = breadcrumb.slice(0, index + 1) // now breadcrumb = ['a', 'b'];

Answer 2

Im pretty sure the accepted answer from this SO question is exactly what you are looking for:

 var array = ['one', 'two', 'three', 'four']; array.length = 2; alert(array); 

Answer 3

You should use array.splice to remove from next element

Syntax: array.splice(index, deleteCount)

 var data= ['a', 'b', 'c', 'd']; data.splice(1+1); console.log(data) 

Answer 4

There are various ways of achieving this.

As you said you know the index of the position from where you need to pop all the elements 1.

var position=2
var breadcrumb = [a, b, c, d];
var length=breadcrumb.length;
var loop;
for(loop=position;loop<length;loop++)
breadcrumb.pop();

2. You can use slice to do this.

    var position=2;
    var breadcrumb = ["a", 'b', 'c', 'd'];
    var length=breadcrumb.length;
    var result_arr=breadcrumb.slice(0,position);

3.You can also use splice to do this

    var position=2;
    var breadcrumb = ["a", 'b', 'c', 'd'];
    var length=breadcrumb.length;
    var result_arr=breadcrumb.splice(0,position);