# Argument Function
> Create an argument function.
## Usage
```javascript
var argumentFunction = require( '@stdlib/utils/argument-function' );
```
#### argumentFunction( idx )
Returns a `function` which always returns an argument corresponding to a specified argument index.
```javascript
var argn = argumentFunction( 1 );
// returns
var v = argn( 1.0, 2.0, 3.0 );
// returns 2.0
v = argn( 'a', 'b', 'c' );
// returns 'b'
```
If an argument function is provided fewer arguments than the specified argument index, an argument function returns `undefined`.
```javascript
var argn = argumentFunction( 100 );
// returns
var v = argn( 1.0 );
// returns undefined
```
## Notes
- Argument indices are **zero-based**.
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var argumentFunction = require( '@stdlib/utils/argument-function' );
var argn;
var v;
var i;
argn = argumentFunction( 1 );
for ( i = 0; i < 10; i++ ) {
v = argn( randu(), randu()*10.0, randu()*100.0 );
console.log( v );
}
```