This [[Module Library|XQuery Module]] contains non-deterministic functions for returning computing random values. All functions except for {{Function||random:seeded-double}} and {{Function||random:seeded-integer}} are nondeterministic, i. e., they return different values for each call.
=Conventions=
All functions and errors in this module are assigned to the {{Code|<code><nowiki>http://basex.org/modules/random}} </nowiki></code> namespace, which is statically bound to the {{Code|random}} prefix.<br/>All errors are assigned to the {{Code|http://basex.org/errors}} namespace, which is statically bound to the {{Code|bxerr}} prefix.
=Functions=
==random:double==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|<pre>random:double||() as xs:double}}<br /pre>|-valign="top"
| '''Summary'''
|Returns a double value between 0.0 (inclusive) and 1.0 (exclusive).<br />|-| |
|}
==random:integer==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|random:integer||xs:integer}}<br /pre>{{Func|random:integer|( $max as xs:integer| := ()) as xs:integer}}<br /pre>|-valign="top"
| '''Summary'''
|Returns an integer value, either in the whole integer range or between 0 (inclusive) and the given maximum (exclusive)<br />|-valign="top"| '''Errors'''|{{Error|bounds|#Errors}} the maximum value is out of bounds.
|}
==random:seeded-double==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|<pre>random:seeded-double|( $seed as xs:integer, $num as xs:integer|) as xs:double*}}<br /pre>|-valign="top"
| '''Summary'''
|Returns a sequence with {{Code|$num}} double values between 0.0 (inclusive) and 1.0 (exclusive). The random values are created using the initial seed given in {{Code|$seed}}.<br />|-| |
|}
==random:seeded-integer==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|random:seeded-integer|$seed as xs:integer, $num as xs:integer|xs:integer*}}<br /pre>{{Func|random:seeded-integer|( $seed as xs:integer, $num as xs:integer, $max as xs:integer| := ()) as xs:integer*}}</pre>|-valign="top"
| '''Summary'''
|Returns a sequence with {{Code|$num}} integer values, either in the whole integer range or between 0 (inclusive) and the given maximum (exclusive). The random values are created using the initial seed given in {{Code|$seed}}.<br />|-valign="top"| '''Errors'''|{{Error|bounds|#Errors}} the maximum value is out of bounds.<br/>{{Error|negative|#Errors}} the number of values to be returned is negative.
|}
==random:gaussian==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|<pre>random:gaussian|( $num as xs:integer|) as xs:double*}}<br /pre>|-valign="top"
| '''Summary'''
|Returns a sequence with {{Code|$num}} double values. The random values are Gaussian (i.e. normally) distributed with the mean 0.0. and the derivation 1.0.<br />|} ==random:seeded-permutation== {| width='100%'|- valign="top"| width='120' | '''Signature'''|<pre>random:seeded-permutation( $seed as xs:integer, $items as item()*) as item()*</pre>| - valign="top"|'''Summary'''|Returns a random permutation of the specified {{Code|$items}}. The random order is created using the initial seed given in {{Code|$seed}}.<br/>
|}
==random:uuid==
{|width='100%'|-valign="top"| width='90120' | '''SignaturesSignature'''|{{Func|<pre>random:uuid||() as xs:string}}</pre>|-valign="top"
| '''Summary'''
|Creates a random universally unique identifier (UUID), represented as 128-bit value.
|-valign="top"
| '''Examples'''
|
* {{Code|mathrandom:uuid() eq mathrandom:uuid()}} will (most probably) return the boolean value {{Code|false}}.|} =Errors= {| class="wikitable" width="100%"! width="110"|Code|Description|- valign="top"|{{Code|bounds}}|The specified maximum value is out of bounds.|- valign="top"|{{Code|negative}}|The specified number of values to be returned is negative.
|}
=Changelog=
The ;Version 9.0 * Updated: error codes updated; errors now use the module was introduced with namespace ;Version 78.45 * Added: {{Function||random:seeded-permutation}} ;Version 8. It includes some functionality which was previously located in the [[Math_Module0 * Updated: {{Function||random:integer}}, {{Function||Math Module]]random:seeded-integer}} raise error for invalid input.
The module was introduced with Version 7.5. It includes some functionality which was previously located in the [[Category:XQueryMath_Module|Math Module]].