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[[Category:XQuery]]
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This [[Module Library|XQuery Module]] contains functions for computing random values. All functions except for {{Code[[#random:seeded-double|random:seeded-double}} ]] and {{Code[[#random:seeded-integer|random:seeded-integer}} ]] are non-deterministic, 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%'
|-
| '''Summary'''
|Returns a double value between 0.0 (inclusive) and 1.0 (exclusive).<br />
|}
==random:integer==
{| width='100%'
|-
|Returns an integer value, either in the whole integer range or between 0 (inclusive) and the given maximum (exclusive)<br />
|-
| '''Errors'''|{{Error|bounds|#Errors}} the maximum value is out of bounds.
|}
==random:seeded-double==
{| width='100%'
|-
| '''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%'
|-
|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 />
|-
| '''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%'
|-
| '''Summary'''
|Returns a sequence with {{Code|$num}} double values. The random values are Gaussian (i.e. normally) distributed with the mean 0.0. and the derivation 1.0.<br />
|}
==random:seeded-permutation==
{| width='100%'
|-
| width='120' | '''Signatures'''
|{{Func|random:seeded-permutation|$seed as xs:integer, $items as item()*|item()*}}
|-
| '''Summary'''|Returns a random permutation of the specified {{Code|$items}}. The random order is created using the initial seed given in {{Code|$seed}}.<br />
|}
==random:uuid==
{| width='100%'
|-
|
* {{Code|random:uuid() eq random:uuid()}} will (most probably) return the boolean value {{Code|false}}.
|}
=Errors=
{| class="wikitable" width="100%"
! width="110"|Code
|Description
|-
|{{Code|bounds}}
|The specified maximum value is out of bounds.
|-
|{{Code|negative}}
|The specified number of values to be returned is negative.
|}
=Changelog=
;Version 9.0
* Updated: error codes updated; errors now use the module namespace
;Version 8.5
* Added: [[#random:seeded-permutation|random:seeded-permutation]]
;Version 8.0
* Updated: [[#random:integer|random:integer]], [[#random:seeded-integer|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 [[Math_Module|Math Module]].
