This XQuery Module contains functions for computing random values. All functions except for random:seeded-double and random:seeded-integer are non-deterministic, i. e., they return different values for each call.
Conventions
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All functions and errors in this module are assigned to the http://basex.org/modules/random
namespace, which is statically bound to the random
prefix.
Functions
random:double
Signatures
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random:double() as xs:double
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Summary
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Returns a double value between 0.0 (inclusive) and 1.0 (exclusive).
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random:integer
Signatures
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random:integer() as xs:integer
random:integer($max as xs:integer) as xs:integer
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Summary
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Returns an integer value, either in the whole integer range or between 0 (inclusive) and the given maximum (exclusive)
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Errors
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bounds : the maximum value is out of bounds.
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random:seeded-double
Signatures
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random:seeded-double($seed as xs:integer, $num as xs:integer) as xs:double*
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Summary
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Returns a sequence with $num double values between 0.0 (inclusive) and 1.0 (exclusive). The random values are created using the initial seed given in $seed .
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random:seeded-integer
Signatures
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random:seeded-integer($seed as xs:integer, $num as xs:integer) as xs:integer*
random:seeded-integer($seed as xs:integer, $num as xs:integer, $max as xs:integer) as xs:integer*
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Summary
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Returns a sequence with $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 $seed .
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Errors
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bounds : the maximum value is out of bounds.
negative : the number of values to be returned is negative.
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random:gaussian
Signatures
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random:gaussian($num as xs:integer) as xs:double*
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Summary
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Returns a sequence with $num double values. The random values are Gaussian (i.e. normally) distributed with the mean 0.0. and the derivation 1.0.
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random:seeded-permutation
Signatures
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random:seeded-permutation($seed as xs:integer, $items as item()*) as item()*
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Summary
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Returns a random permutation of the specified $items . The random order is created using the initial seed given in $seed .
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random:uuid
Signatures
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random:uuid() as xs:string
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Summary
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Creates a random universally unique identifier (UUID), represented as 128-bit value.
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Examples
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random:uuid() eq random:uuid() will (most probably) return the boolean value false .
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Errors
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Code
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Description
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bounds
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The specified maximum value is out of bounds.
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negative
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The specified number of values to be returned is negative.
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Changelog
- Version 9.0
- Updated: error codes updated; errors now use the module namespace
- Version 8.5
- Version 8.0
The module was introduced with Version 7.5. It includes some functionality which was previously located in the Math Module.