152 lines
4.1 KiB
Markdown
152 lines
4.1 KiB
Markdown
<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# pop
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> Remove and return the last element of a collection.
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<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->
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<section class="intro">
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</section>
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<!-- /.intro -->
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<!-- Package usage documentation. -->
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<section class="usage">
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## Usage
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```javascript
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var pop = require( '@stdlib/utils/pop' );
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```
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#### pop( collection )
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Removes and returns the last element of a `collection`. A `collection` may be either an [`Array`][mdn-array], [`Typed Array`][mdn-typed-array], or an array-like [`Object`][mdn-object] (i.e., an [`Object`][mdn-object] having a valid writable `length` property).
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```javascript
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var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];
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var out = pop( arr );
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// returns [ [ 1.0, 2.0, 3.0, 4.0 ], 5.0 ]
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var bool = ( out[ 0 ] === arr );
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// returns true
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var lastValue = out[ 1 ];
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// returns 5.0
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```
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In contrast to [`Array.prototype.pop`][mdn-array-pop] which returns only the removed element, the function also returns the shortened collection. For [typed arrays][mdn-typed-array] having a length greater than `0`, the returned collection is a new [typed array][mdn-typed-array] view.
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```javascript
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var Float64Array= require( '@stdlib/array/float64' );
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var arr = new Float64Array( 2 );
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arr[ 0 ] = 1.0;
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arr[ 1 ] = 2.0;
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var out = pop( arr );
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// returns [ <Float64Array>[ 1.0 ], 2.0 ]
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var bool = ( out[ 0 ] === arr );
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// returns false
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bool = ( out[ 0 ].buffer === arr.buffer );
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// returns true
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var lastValue = out[ 1 ];
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// returns 2.0
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```
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</section>
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<!-- /.usage -->
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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="notes">
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## Notes
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- When provided a [typed array][mdn-typed-array], the function does **not** change the underlying [`ArrayBuffer`][mdn-arraybuffer]. The function returns a new [typed array][mdn-typed-array] view whose length is one less than the input [typed array][mdn-typed-array] length. Accordingly, the function does **not** reduce the memory footprint of an input [typed array][mdn-typed-array].
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</section>
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<!-- /.notes -->
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<!-- Package usage examples. -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var Float64Array= require( '@stdlib/array/float64' );
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var pop = require( '@stdlib/utils/pop' );
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var arr;
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var out;
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var i;
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arr = new Float64Array( 100 );
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for ( i = 0; i < 100; i++ ) {
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out = pop( arr );
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arr = out[ 0 ];
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console.log( 'Length: %d', arr.length );
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}
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console.log( arr );
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```
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</section>
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<!-- /.examples -->
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<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="references">
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</section>
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<!-- /.references -->
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<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->
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<section class="links">
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[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array
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[mdn-array-pop]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/pop
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[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays
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[mdn-arraybuffer]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer
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[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object
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</section>
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<!-- /.links -->
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