npm package: @stdlib/ndarray-base-singleton-dimensions
Description: Return the number of singleton dimensions.
Author: The Stdlib Authors
Latest version: 0.2.3

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# Singleton Dimensions

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> Return the number of singleton dimensions.

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/ndarray-base-singleton-dimensions
```

</section>

<section class="usage">

## Usage

```javascript
var singletonDimensions = require( '@stdlib/ndarray-base-singleton-dimensions' );
```

#### singletonDimensions( shape )

Returns the number of singleton dimensions.

```javascript
var n = singletonDimensions( [ 3, 1, 3 ] );
// returns 1
```

</section>

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<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   A singleton dimension is a dimension whose size is equal to `1`.

</section>

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<section class="examples">

## Examples

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

```javascript
var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var singletonDimensions = require( '@stdlib/ndarray-base-singleton-dimensions' );

var shape;
var n;
var i;

shape = [ 0, 0, 0 ];
for ( i = 0; i < 100; i++ ) {
    shape[ 0 ] = discreteUniform( 1, 5 );
    shape[ 1 ] = discreteUniform( 1, 5 );
    shape[ 2 ] = discreteUniform( 1, 5 );
    n = singletonDimensions( shape );
    console.log( 'shape: %s. singleton dimensions: %d.', shape.join( 'x' ), n );
}
```

</section>

<!-- /.examples -->

<!-- C interface documentation. -->

* * *

<section class="c">

## C APIs

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</section>

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<section class="usage">

### Usage

```c
#include "stdlib/ndarray/base/singleton_dimensions.h"
```

#### stdlib_ndarray_singleton_dimensions( ndims, \*shape )

Returns the number of singleton dimensions.

```c
int64_t ndims = 2;
int64_t shape[] = { 10, 1 };

int64_t n = stdlib_ndarray_singleton_dimensions( ndims, shape );
// returns 1
```

The function accepts the following arguments:

-   **ndims**: `[in] int64_t` number of dimensions.
-   **shape**: `[in] int64_t*` array shape.

```c
int64_t stdlib_ndarray_singleton_dimensions( int64_t ndims, int64_t *shape );
```

</section>

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<section class="notes">

</section>

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<!-- C API usage examples. -->

<section class="examples">

### Examples

```c
#include "stdlib/ndarray/base/singleton_dimensions.h"
#include <stdio.h>
#include <inttypes.h>

int main( void ) {
    int64_t shape[] = { 10, 3, 1, 1, 5 };

    int64_t n = stdlib_ndarray_singleton_dimensions( 5, shape );
    printf( "shape: %"PRId64"x%"PRId64"x%"PRId64"x%"PRId64"x%"PRId64". singleton dimensions: %"PRId64"\n", shape[ 0 ], shape[ 1 ], shape[ 2 ], shape[ 3 ], shape[ 4 ], n );
}
```

</section>

<!-- /.examples -->

</section>

<!-- /.c -->

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</section>

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* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

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## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

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