112 lines
2.1 KiB
Markdown
112 lines
2.1 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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# isEven
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> Test if a finite numeric value is an even number.
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<section class="usage">
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## Usage
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```javascript
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var isEven = require( '@stdlib/math/base/assert/is-even' );
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```
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#### isEven( x )
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Tests if a **finite** `numeric` value is an even number.
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```javascript
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var bool = isEven( 5.0 );
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// returns false
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bool = isEven( -2.0 );
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// returns true
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bool = isEven( 0.0 );
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// returns true
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bool = isEven( NaN );
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// returns false
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```
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</section>
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<!-- /.usage -->
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<section class="notes">
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## Notes
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- The function assumes a **finite** `number`. If provided positive or negative `infinity`, the function will return `true`, when, in fact, the result is undefined. If `x` can be `infinite`, wrap the implementation as follows:
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```javascript
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function check( x ) {
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return (
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x < Infinity &&
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x > -Infinity &&
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isEven( x )
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);
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}
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var bool = check( Infinity );
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// returns false
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bool = check( -Infinity );
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// returns false
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```
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</section>
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<!-- /.notes -->
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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 round = require( '@stdlib/math/base/special/round' );
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var isEven = require( '@stdlib/math/base/assert/is-even' );
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var bool;
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var x;
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var i;
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for ( i = 0; i < 100; i++ ) {
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x = round( randu()*100.0 );
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bool = isEven( x );
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console.log( '%d is %s', x, ( bool ) ? 'even' : 'not even' );
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}
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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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