# incrsummary
> Compute a statistical summary incrementally.
## Usage
```javascript
var incrsummary = require( '@stdlib/stats/incr/summary' );
```
#### incrsummary()
Returns an accumulator `function` which incrementally computes a statistical summary.
```javascript
var accumulator = incrsummary();
```
#### accumulator( \[x] )
If provided an input value `x`, the accumulator function returns an updated summary. If not provided an input value `x`, the accumulator function returns the current summary.
```javascript
var accumulator = incrsummary();
var summary = accumulator();
// returns {}
summary = accumulator( 2.0 );
/* returns
{
'count': 1,
'max': 2.0,
'min': 2.0,
'range': 0.0,
'midrange': 2.0,
'sum': 2.0,
'mean': 2.0,
'variance': 0.0,
'stdev': 0.0,
'skewness': null,
'kurtosis': null
}
*/
summary = accumulator( 1.0 );
/* returns
{
'count': 2,
'max': 2.0,
'min': 1.0,
'range': 1.0,
'midrange': 1.5,
'sum': 3.0,
'mean': 1.5,
'variance': 0.5,
'stdev': 0.7071067811865476,
'skewness': null,
'kurtosis': null
}
*/
summary = accumulator( -3.0 );
/* returns
{
'count': 3,
'max': 2.0,
'min': -3.0,
'range': 5.0,
'midrange': -0.5,
'sum': 0.0,
'mean': 0.0,
'variance': 7,
'stdev': ~2.65,
'skewness': ~-1.46,
'kurtosis': null
}
*/
summary = accumulator();
/* returns
{
'count': 3,
'max': 2.0,
'min': -3.0,
'range': 5.0,
'midrange': -0.5,
'sum': 0.0,
'mean': 0.0,
'variance': 7,
'stdev': ~2.65,
'skewness': ~-1.46,
'kurtosis': null
}
*/
```
## Notes
- Input values are **not** type checked. If non-numeric inputs are possible, you are advised to type check and handle accordingly **before** passing the value to the accumulator function.
- For long running accumulations or accumulations of large numbers, care should be taken to prevent overflow.
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var incrsummary = require( '@stdlib/stats/incr/summary' );
var accumulator;
var v;
var i;
// Initialize an accumulator:
accumulator = incrsummary();
// For each simulated datum, update the summary...
for ( i = 0; i < 100; i++ ) {
v = randu() * 100.0;
accumulator( v );
}
console.log( accumulator() );
```