4.1 KiB
4.1 KiB
pop
Remove and return the last element of a collection.
Usage
var pop = require( '@stdlib/utils/pop' );
pop( collection )
Removes and returns the last element of a collection
. A collection
may be either an Array
, Typed Array
, or an array-like Object
(i.e., an Object
having a valid writable length
property).
var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
var out = pop( arr );
// returns [ [ 1.0, 2.0, 3.0, 4.0 ], 5.0 ]
var bool = ( out[ 0 ] === arr );
// returns true
var lastValue = out[ 1 ];
// returns 5.0
In contrast to Array.prototype.pop
which returns only the removed element, the function also returns the shortened collection. For typed arrays having a length greater than 0
, the returned collection is a new typed array view.
var Float64Array= require( '@stdlib/array/float64' );
var arr = new Float64Array( 2 );
arr[ 0 ] = 1.0;
arr[ 1 ] = 2.0;
var out = pop( arr );
// returns [ <Float64Array>[ 1.0 ], 2.0 ]
var bool = ( out[ 0 ] === arr );
// returns false
bool = ( out[ 0 ].buffer === arr.buffer );
// returns true
var lastValue = out[ 1 ];
// returns 2.0
Notes
- When provided a typed array, the function does not change the underlying
ArrayBuffer
. The function returns a new typed array view whose length is one less than the input typed array length. Accordingly, the function does not reduce the memory footprint of an input typed array.
Examples
var Float64Array= require( '@stdlib/array/float64' );
var pop = require( '@stdlib/utils/pop' );
var arr;
var out;
var i;
arr = new Float64Array( 100 );
for ( i = 0; i < 100; i++ ) {
out = pop( arr );
arr = out[ 0 ];
console.log( 'Length: %d', arr.length );
}
console.log( arr );