# nans
> Create a NaN-filled [ndarray][@stdlib/ndarray/ctor] having a specified shape and [data type][@stdlib/ndarray/dtypes].
## Usage
```javascript
var nans = require( '@stdlib/ndarray/nans' );
```
#### nans( shape\[, options] )
Creates a NaN-filled [ndarray][@stdlib/ndarray/ctor] having a specified shape and [data type][@stdlib/ndarray/dtypes].
```javascript
var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );
var arr = nans( [ 2, 2 ] );
// returns [ [ NaN, NaN ], [ NaN, NaN ] ]
var sh = getShape( arr );
// returns [ 2, 2 ]
var dt = String( getDType( arr ) );
// returns 'float64'
```
The specified output [ndarray][@stdlib/ndarray/ctor] shape may be either an array-like object or an integer value.
```javascript
var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );
var arr = nans( 2 );
// returns [ NaN, NaN ]
var sh = getShape( arr );
// returns [ 2 ]
var dt = String( getDType( arr ) );
// returns 'float64'
```
The function accepts the following options:
- **dtype**: underlying [data type][@stdlib/ndarray/dtypes]. Must be a floating-point or "generic" [data type][@stdlib/ndarray/dtypes]. Default: `'float64'`.
- **order**: specifies whether an [ndarray][@stdlib/ndarray/ctor] is `'row-major'` (C-style) or `'column-major'` (Fortran-style). Default: `'row-major'`.
- **mode**: specifies how to handle indices which exceed array dimensions (see [ndarray][@stdlib/ndarray/ctor]). Default: `'throw'`.
- **submode**: a mode array which specifies for each dimension how to handle subscripts which exceed array dimensions (see [ndarray][@stdlib/ndarray/ctor]). If provided fewer modes than dimensions, the constructor recycles modes using modulo arithmetic. Default: `[ options.mode ]`.
- **readonly**: boolean indicating whether an array should be **read-only**. Default: `false`.
By default, the function returns an [ndarray][@stdlib/ndarray/ctor] having a [`float64`][@stdlib/ndarray/dtypes] data type. To specify an alternative [data type][@stdlib/ndarray/dtypes], provide a `dtype` option.
```javascript
var getShape = require( '@stdlib/ndarray/shape' );
var getDType = require( '@stdlib/ndarray/dtype' );
var arr = nans( [ 2, 2 ], {
'dtype': 'float32'
});
// returns [ [ NaN, NaN ], [ NaN, NaN ] ]
var sh = getShape( arr );
// returns [ 2, 2 ]
var dt = String( getDType( arr ) );
// returns 'float32'
```
## Examples
```javascript
var ndarray2array = require( '@stdlib/ndarray/to-array' );
var nans = require( '@stdlib/ndarray/nans' );
// Specify a list of data types:
var dt = [
'float64',
'float32',
'complex128',
'complex64',
'generic'
];
// Generate NaN-filled arrays...
var arr;
var i;
for ( i = 0; i < dt.length; i++ ) {
arr = nans( [ 2, 2 ], {
'dtype': dt[ i ]
});
console.log( ndarray2array( arr ) );
}
```
[@stdlib/ndarray/ctor]: https://github.com/stdlib-js/ndarray/tree/main/ctor
[@stdlib/ndarray/dtypes]: https://github.com/stdlib-js/ndarray/tree/main/dtypes