Hi, Ken,
I recently had to build a permutation generator to generate all the unique
combinations of a set of
data where (just as in your case) order was not a factor. So given the data
set "A,B,C", I needed
to get out:
A,B,C
A,B
B,C
A,C
A
B
C
I looked at my code and was able to modify it to (hopefully) suit your purpose.
It requires using recursion, so most of the work is done in a CFC function.
Here's the code for the CFC:
<cfcomponent displayname="Permutations" hint="I generate the permutations."
output="false">
<cffunction name="generatePermutations" output="true"
returntype="string" hint="I return a list of all possible combinations of a
list of items where the order of the items is constant but one or more items
can be missing">
<cfargument name="starting_list" type="string" required="yes" hint="The
starting list of items. The list will grow smaller via recursion." />
<cfargument name="permutation_list" type="string" required="yes"
hint="The current list of permutations, which will grow longer." />
<cfargument name="start_delimiter" type="string" required="yes"
hint="The list delimiter." />
<cfargument name="perm_delimiter" type="string" required="yes"
hint="The delimiter for the final list. Should be different from
start_delimiter" />
<cfset var temp= "">
<cfset var p_list= arguments.permutation_list>
<!---Determine if the full list of items is already in the permutations
list. If not, add it--->
<cfif Not
ListFind(p_list,arguments.starting_list,arguments.perm_delimiter) AND
ListLen(arguments.starting_list,",") EQ 6>
<cfset p_list=
ListAppend(p_list,arguments.starting_list,arguments.perm_delimiter)>
</cfif>
<!---If starting_list length is not 6, loop and call the function for
each iteration of the loop--->
<cfif ListLen(arguments.starting_list,arguments.start_delimiter) GT 6>
<cfloop index="gone" from="1"
to="#ListLen(arguments.starting_list,arguments.start_delimiter)#">
<cfset temp=
ListDeleteAt(arguments.starting_list,gone,arguments.start_delimiter)>
<cfinvoke component="Permutations"
method="generatePermutations" returnvariable="p_list" starting_list="#temp#"
permutation_list="#p_list#" start_delimiter="#arguments.start_delimiter#"
perm_delimiter="#arguments.perm_delimiter#"></cfinvoke>
</cfloop>
</cfif>
<cfreturn p_list />
</cffunction>
</cfcomponent>
....And here's the code for a page that you can use to test it:
<cfsetting requesttimeout="600">
<cfoutput>
<cfset inputValues1= '1,2,3,4,5,6,7,'>
<cfset inputValues2= '1,2,3,4,5,6,7,8,9,10,11,12'>
<p>
inputValues1 is: #inputValues1#
</p>
<cfinvoke component="Permutations" method="generatePermutations"
starting_list="#inputValues1#" permutation_list="" start_delimiter=","
perm_delimiter="|" returnvariable="fullPermutationList"></cfinvoke>
<p>List the permutations:</p>
<ul>
<cfloop index="combo" list="#fullPermutationList#" delimiters="|">
<li>#combo#</li>
</cfloop>
</ul>
</cfoutput>
....It can render your "1,2,3,4,5,6,7" example pretty quickly, but it takes a
pretty long time to do something larger like a 12-item set (hence the
<cfsetting> tag to increase the timeout), and I didn't have the time to figure
out how much time it would take to process a full 20-item list.
Maybe there's a better way to do it, but hopefully this at least provides a
starting point.
--
Brian Swartzfager
[EMAIL PROTECTED]
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