# Exponential > Exponential distribution.
## Usage ```javascript var exponential = require( '@stdlib/stats/base/dists/exponential' ); ``` #### exponential Exponential distribution. ```javascript var dist = exponential; // returns {...} ``` The namespace contains the following distribution functions:
- [`cdf( x, lambda )`][@stdlib/stats/base/dists/exponential/cdf]: exponential distribution cumulative distribution function. - [`logcdf( x, lambda )`][@stdlib/stats/base/dists/exponential/logcdf]: evaluate the natural logarithm of the cumulative distribution function for an exponential distribution. - [`logpdf( x, lambda )`][@stdlib/stats/base/dists/exponential/logpdf]: evaluate the natural logarithm of the probability density function (PDF) for an exponential distribution. - [`mgf( t, lambda )`][@stdlib/stats/base/dists/exponential/mgf]: exponential distribution moment-generating function (MGF). - [`pdf( x, lambda )`][@stdlib/stats/base/dists/exponential/pdf]: exponential distribution probability density function (PDF). - [`quantile( p, lambda )`][@stdlib/stats/base/dists/exponential/quantile]: exponential distribution quantile function.
The namespace contains the following functions for calculating distribution properties:
- [`entropy( lambda )`][@stdlib/stats/base/dists/exponential/entropy]: exponential distribution differential entropy. - [`kurtosis( lambda )`][@stdlib/stats/base/dists/exponential/kurtosis]: exponential distribution excess kurtosis. - [`mean( lambda )`][@stdlib/stats/base/dists/exponential/mean]: exponential distribution expected value. - [`median( lambda )`][@stdlib/stats/base/dists/exponential/median]: exponential distribution median. - [`mode( lambda )`][@stdlib/stats/base/dists/exponential/mode]: exponential distribution mode. - [`skewness( lambda )`][@stdlib/stats/base/dists/exponential/skewness]: exponential distribution skewness. - [`stdev( lambda )`][@stdlib/stats/base/dists/exponential/stdev]: exponential distribution standard deviation. - [`variance( lambda )`][@stdlib/stats/base/dists/exponential/variance]: exponential distribution variance.
The namespace contains a constructor function for creating an [exponential][exponential-distribution] distribution object.
- [`Exponential( [lambda] )`][@stdlib/stats/base/dists/exponential/ctor]: exponential distribution constructor.
```javascript var Exponential = require( '@stdlib/stats/base/dists/exponential' ).Exponential; var dist = new Exponential( 2.0 ); var y = dist.logpdf( 0.8 ); // returns ~-0.907 ```
## Examples ```javascript var objectKeys = require( '@stdlib/utils/keys' ); var exponential = require( '@stdlib/stats/base/dists/exponential' ); console.log( objectKeys( exponential ) ); ```