@stdlib/utils/tabulate/README.md

Standard utilities.

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# tabulate

> Generate a frequency table.

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## Usage

```javascript
var tabulate = require( '@stdlib/utils/tabulate' );
```

#### tabulate( collection )

Generates a frequency table.

```javascript
var arr = [ 'beep', 'boop', 'foo', 'beep' ];

var out = tabulate( arr );
// returns [ [ 'beep', 2, 0.5 ], [ 'boop', 1, 0.25 ], [ 'foo', 1, 0.25 ] ]
```

The returned frequency table is an `array` of `arrays`. Each sub-array corresponds to a unique value in the input `collection` and is structured as follows:

-   `0`: unique value
-   `1`: value count
-   `2`: frequency percentage

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## Notes

-   A `collection` may be either an [`Array`][mdn-array], [`Typed Array`][mdn-typed-array], or an array-like [`Object`][mdn-object] (excluding `strings` and `functions`).

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## Examples

<!-- eslint no-undef: "error" -->

```javascript
var randu = require( '@stdlib/random/base/randu' );
var floor = require( '@stdlib/math/base/special/floor' );
var tabulate = require( '@stdlib/utils/tabulate' );

var vals;
var arr;
var out;
var i;
var j;

vals = [ 'beep', 'boop', 'foo', 'bar', 'woot', 'woot' ];

// Generate a random collection...
arr = new Array( 100 );
for ( i = 0; i < arr.length; i++ ) {
    j = floor( randu()*vals.length );
    arr[ i ] = vals[ j ];
}

// Generate a frequency table:
out = tabulate( arr );
console.log( out );
```

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* * *

## See Also

-   <span class="package-name">[`@stdlib/utils/count-by`][@stdlib/utils/count-by]</span><span class="delimiter">: </span><span class="description">group values according to an indicator function and return group counts.</span>
-   <span class="package-name">[`@stdlib/utils/group-by`][@stdlib/utils/group-by]</span><span class="delimiter">: </span><span class="description">group values according to an indicator function.</span>
-   <span class="package-name">[`@stdlib/utils/tabulate-by`][@stdlib/utils/tabulate-by]</span><span class="delimiter">: </span><span class="description">generate a frequency table according to an indicator function.</span>

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[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

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[@stdlib/utils/count-by]: https://github.com/stdlib-js/utils/tree/main/count-by

[@stdlib/utils/group-by]: https://github.com/stdlib-js/utils/tree/main/group-by

[@stdlib/utils/tabulate-by]: https://github.com/stdlib-js/utils/tree/main/tabulate-by

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