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Randomize

Last updated on Jun 11, 2024 | Also applies to ColdFusion

ColdFusion

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CFML Reference User Guide
ColdFusion functions
ColdFusion Tags
1. ColdFusion tag summary
2. ColdFusion tags by category
  1. Application framework tags
    1. cfapplication
    2. cfassociate
    3. cferror
    4. cfimport
    5. cfinterface
    6. cflock
    7. cfscript
    8. cfthread
  2. Communications tags
  3. Database manipulation tags
  4. Data output tags
    1. cfchart
    2. cfchartdata
    3. cfchartseries
    4. cfcol
    5. cfcontent
    6. cfdocument
    7. cfdocumentitem
    8. cfdocumentsection
    9. cfflush
    10. cfheader
    11. cflog
    12. cfoutput
    13. cfpresentation
    14. cfpresentationslide
    15. cfpresenter
    16. cfprocessingdirective
    17. cfprint
    18. cfreport
    19. cfreportparam
    20. cfsilent
    21. cftable
  5. Debugging tags
    1. cfdump
    2. cftimer
    3. cftrace
  6. Exception handling tags
    1. cfcatch
    2. cferror
    3. cffinally
    4. cfrethrow
    5. cfthrow
    6. cftry
  7. Extensibility tags
    1. cfchart
    2. cfchartdata
    3. cfchartseries
    4. cfcollection
    5. cfcomponent
    6. cfexecute
    7. cfftp
    8. function
    9. cfindex
    10. cfinterface
    11. cfinvoke
    12. cfinvokeargument
    13. cfobject
    14. cfproperty
    15. cfreport
    16. cfreportparam
    17. cfreturn
    18. cfsearch
    19. cfsharepoint
    20. cfspreadsheet
    21. cfwddx
    22. cfxml
  8. File management tags
    1. cfdirectory
    2. cffile
    3. cffileupload
    4. cfftp
    5. cfzip
    6. cfzipparam
  9. Flow-control tags
    1. cfabort
    2. cfbreak
    3. cfcase
    4. cfcontinue
    5. cfdefaultcase
    6. cfelse
    7. cfelseif
    8. cfexecute
    9. cfexit
    10. cfif
    11. cfinclude
    12. cflocation
    13. cfloop
    14. cfrethrow
    15. cfswitch
    16. cfthrow
    17. cftry
  10. Forms tags
    1. cfapplet
    2. cfcalendar
    3. cffileupload
    4. cfform
    5. cfformgroup
    6. cfformitem
    7. cfgrid
    8. cfgridcolumn
    9. cfgridrow
    10. cfgridupdate
    11. cfinput
    12. cfpdf
    13. cfpdfform
    14. cfpdfformparam
    15. cfpdfparam
    16. cfpdfsubform
    17. cfselect
    18. cfslider
    19. cftextarea
    20. cftree
    21. cftreeitem
  11. Internet Protocol tags
    1. cfajaximport
    2. cfajaxproxy
    3. cfftp
    4. cffeed
    5. cfimap
    6. cfhttp
    7. cfhttpparam
    8. cfldap
    9. cfmail
    10. cfmailparam
    11. cfmailpart
    12. cfpop
    13. cfsprydataset
  12. Page processing tags
    1. cfcache
    2. cfcontent
    3. cfflush
    4. cfheader
    5. cfhtmlhead
    6. cfinclude
    7. cfprocessingdirective
    8. cfsetting
    9. cfsilent
  13. Security tags
  14. Variable manipulation tags
    1. cfcookie
    2. cfdump
    3. cfparam
    4. cfregistry
    5. cfsavecontent
    6. cfschedule
    7. cfset
    8. cfsetting
  15. Other tags
    1. cfimage
    2. cflog
    3. cfregistry
3. Tags a-b
4. Tags c
  1. cfcache
  2. cfcalendar
  3. cfcase
  4. cfcatch
  5. cfchart
  6. cfchartdata
  7. cfchartseries
  8. cfclient
  9. cfclientsettings
  10. cfcol
  11. cfcollection
  12. cfcomponent
  13. cfcontent
  14. cfcontinue
  15. cfcookie
  16. Tags d-e
5. Tags f
6. Tags g-h
  1. cfgraph
  2. cfgraphdata
  3. cfgrid
  4. cfgridcolumn
  5. cfgridrow
  6. cfgridupdate
  7. cfheader
  8. cfhtmlhead
  9. cfhtmltopdf
  10. cfhtmltopdfitem
  11. cfhttp
  12. cfhttpparam
7. Tags i
  1. cfif
  2. cfimage
  3. cfimap
  4. cfimapfilter
  5. cfimpersonate
  6. cfimport
  7. cfinclude
  8. cfindex
  9. cfinput
  10. cfinsert
  11. cfinterface
  12. cfinvoke
  13. cfinvokeargument
8. Tags j-l
9. Tags m-o
10. Tags p-q
  1. cfparam
  2. cfpdf
  3. cfpdfform
  4. cfpdfformparam
  5. cfpdfparam
  6. cfpdfsubform
  7. cfpod
  8. cfpop
  9. cfpresentation
  10. cfpresentationslide
  11. cfpresenter
  12. cfprint
  13. cfprocessingdirective
  14. cfprocparam
  15. cfprocresult
  16. cfprogressbar
  17. cfproperty
  18. cfquery
  19. cfqueryparam
11. Tags r-s
  1. cfregistry
  2. cfreport
  3. cfreportparam
  4. cfrethrow
  5. cfreturn
  6. cfsavecontent
  7. cfschedule
  8. cfscript
  9. cfsearch
  10. cfselect
  11. cfservlet
  12. cfservletparam
  13. cfset
  14. cfsetting
  15. cfsharepoint
  16. cfsilent
  17. cfslider
  18. cfspreadsheet
  19. cfsprydataset
  20. cfstoredproc
  21. cfswitch
12. Tags t
  1. cftable
  2. cftextarea
  3. cftextinput
  4. cfthread
  5. cfthrow
  6. cftimer
  7. cftooltip
  8. cftrace
  9. cftransaction
  10. cftree
  11. cftreeitem
  12. cftry
13. Tags u-z
  1. cfupdate
  2. cfwddx
  3. cfwebsocket
  4. cfwindow
  5. cfxml
  6. cfzip
  7. cfzipparam
CFML Reference
1. Reserved words and variables
2. Ajax JavaScript functions
3. ColdFusion ActionScript functions
4. ColdFusion mobile functions
5. Application.cfc reference
6. Script functions implemented as CFCs
7. ColdFusion Flash Form style reference
8. ColdFusion event gateway reference
9. ColdFusion C++ CFX Reference
10. ColdFusion Java CFX reference
11. WDDX JavaScript Objects
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Description

Seeds the pseudo-random number generator with an integer number, ensuring repeatable number patterns.

Returns

A pseudo-random decimal number, in the range 0-1.

Function syntax

Randomize(number[, algorithm])

History

ColdFusion (2023 release) Update 8 and ColdFusion (2021 release) Update 14: Changed the default algorithm from CFMX_COMPAT to SHA1PRNG.
ColdFusion MX 7: Added the algorithm parameter.

Parameters

Parameter	Description
number	Integer number. If the number is not in the range -2,147,483,648 -2,147,483,647, ColdFusion generates an error.
algorithm	(Optional) The algorithm to use to generate the seed number. ColdFusion installs a cryptography library with the following algorithms: CFMX_COMPAT: the algorithm used in ColdFusion. SHA1PRNG: generates a number using the Sun Java SHA1PRNG algorithm. This algorithm provides greater randomness than the default algorithm. Note: due to a bug in ColdFusion 9, 10 and 11, this option does not work as prescribed. See bug 3792283 for details. (Default) IBMSecureRandom: for IBM WebSphere (IBM JVM does not support the SHA1PRNG algorithm).

Parameter

Description

number

Integer number. If the number is not in the range -2,147,483,648 -2,147,483,647, ColdFusion generates an error.

algorithm

(Optional) The algorithm to use to generate the seed number. ColdFusion installs a cryptography library with the following algorithms:

CFMX_COMPAT: the algorithm used in ColdFusion.
SHA1PRNG: generates a number using the Sun Java SHA1PRNG algorithm. This algorithm provides greater randomness than the default algorithm. Note: due to a bug in ColdFusion 9, 10 and 11, this option does not work as prescribed. See bug 3792283 for details. (Default)
IBMSecureRandom: for IBM WebSphere (IBM JVM does not support the SHA1PRNG algorithm).

Usage

Call this function before calling Rand to seed the random number generator. Seeding the generator ensures that the Rand function always generates the same sequence of pseudo-random numbers. This behavior is useful if you must reproduce a pattern consistently.In Standard Edition, for all algorithms except the default algorithm, ColdFusion uses the Java Cryptography Extension (JCE) and installs a Sun Java runtime that includes the Sun JCE default security provider. This provider includes the algorithms listed in the Parameters section. The JCE framework includes facilities for using other provider implementations; however, Adobe cannot provide technical support for third-party security providers.In Enterprise Edition, ColdFusion also installs the RSA BSafe Crypto-J library. This provider adds the following algorithms: FIPS186PRNG, MD5PRNG, DummyPRNG, OBFPRNG. DummyPRNG always returns 0.

Note: To get repeatable number of patterns for a given initial seed, JSAFE must be disabled using the JVM argument on enterprise and developer editions as follows:

Dcoldfusion.disablejsafe=true

Example

The following example calls the Randomize function to seed the random number generator and generates 10 random numbers.

<cfset randomize(12345)> <!--- if one was to remove this line, the random numbers are different every time --->
<cfloop index="i" from="1" to="10">
<cfoutput>#rand()#</cfoutput><br>
</cfloop>

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