Array.prototype.pop() - JavaScript 编辑

The pop() method removes the last element from an array and returns that element. This method changes the length of the array.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

arrName.pop()

Return value

The removed element from the array; undefined if the array is empty.

Description

The pop method removes the last element from an array and returns that value to the caller.

pop is intentionally generic; this method can be called or applied to objects resembling arrays. Objects which do not contain a length property reflecting the last in a series of consecutive, zero-based numerical properties may not behave in any meaningful manner.

If you call pop() on an empty array, it returns undefined.

Array.prototype.shift() has similar behavior to pop, but applied to the first element in an array.

Examples

Removing the last element of an array

The following code creates the myFish array containing four elements, then removes its last element.

var myFish = ['angel', 'clown', 'mandarin', 'sturgeon'];

var popped = myFish.pop();

console.log(myFish); // ['angel', 'clown', 'mandarin' ]

console.log(popped); // 'sturgeon'

Using apply( ) or call ( ) on array-like objects

The following code creates the myFish array-like object containing four elements and a length parameter, then removes its last element and decrements the length parameter.

var myFish = {0:'angel', 1:'clown', 2:'mandarin', 3:'sturgeon', length: 4};

var popped = Array.prototype.pop.call(myFish); //same syntax for using apply( )

console.log(myFish); // {0:'angel', 1:'clown', 2:'mandarin', length: 3}

console.log(popped); // 'sturgeon'

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Array.prototype.pop' in that specification.

Browser compatibility

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See also

• Array.prototype.push()
• Array.prototype.shift()
• Array.prototype.unshift()
• Array.prototype.concat()
• Array.prototype.splice()