151 lines
3.4 KiB
Markdown
151 lines
3.4 KiB
Markdown
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<!--
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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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# Zip
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> Generate array tuples from input arrays.
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<section class="intro">
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</section>
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<!-- /.intro -->
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<section class="usage">
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## Usage
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```javascript
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var zip = require( '@stdlib/utils/zip' );
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```
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#### zip( arr1, arr2,...\[, opts] )
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Returns an `array` of `arrays`, where the ith element (tuple) in the returned `array` contains the ith elements of the input `arrays`.
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```javascript
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var zipped = zip( [ 1, 2 ], [ 'a', 'b' ] );
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// returns [ [ 1, 'a' ], [ 2, 'b' ] ]
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```
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By default, the returned `array` length is the length of the shortest input `array`.
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```javascript
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var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ] );
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// returns [ [ 1, 'a' ], [ 2, 'b' ] ]
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```
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The function accepts an `options` object with optional properties:
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- **trunc**: `boolean` specifying whether the returned `array` should truncate `arrays` longer than the shortest `array`. Default: `true`.
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- **fill**: fill value used for unequal length `arrays`. Default: `null`.
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- **arrays**: `boolean` specifying whether, when provided a single input `array`, the function should interpret the argument as a list of `arrays` to be zipped (i.e., behavior similar to `zip.apply(null, arr)`). Default: `false`.
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To turn off truncation,
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```javascript
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var opts = {
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'trunc': false
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};
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var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ], opts );
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// returns [ [ 1, 'a' ], [ 2, 'b' ], [ 3, null ] ]
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```
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A fill value is included in each tuple for each `array` which does not have an element at the ith index. By default, the fill value is `null`. To specify a different fill value, set the `fill` option.
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```javascript
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var opts = {
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'trunc': false,
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'fill': ''
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};
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var zipped = zip( [ 1, 2, 3 ], [ 'a', 'b' ], opts );
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// returns [ [ 1, 'a' ], [ 2, 'b' ], [ 3, '' ] ]
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```
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If the function should interpret a single input `array` as an `array` of `arrays` to be zipped,
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<!-- eslint-disable object-curly-newline -->
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```javascript
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var zipped;
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var arr = [ [ 1, 2 ], [ 'a', 'b' ] ];
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// Default behavior:
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zipped = zip( arr );
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// returns [ [ [ 1, 2 ] ], [ [ 'a', 'b' ] ] ]
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// Array of arrays:
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zipped = zip( arr, { 'arrays': true } );
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// returns [ [ 1, 'a' ], [ 2, 'b' ] ]
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```
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</section>
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<!-- /.usage -->
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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 randu = require( '@stdlib/random/base/randu' );
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var zip = require( '@stdlib/utils/zip' );
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var zipped;
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var len;
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var y1;
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var y2;
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var y3;
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var x;
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var i;
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// Simulate some data...
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x = new Array( 100 );
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len = x.length;
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y1 = new Array( len );
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y2 = new Array( len );
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y3 = new Array( len );
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for ( i = 0; i < len; i++ ) {
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x[ i ] = Date.now();
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y1[ i ] = randu() * 100;
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y2[ i ] = randu() * 100;
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y3[ i ] = randu();
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}
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zipped = zip( x, y1, y2, y3 );
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console.log( zipped.join( '\n' ) );
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```
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</section>
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<!-- /.examples -->
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<section class="links">
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</section>
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<!-- /.links -->
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