How to sort an array of structs in ColdFusion

Question

I have an array of structs in ColdFusion. I'd like to sort this array based on one of the attributes in the structs. How can I achieve this? I've found the StructSort function, but it takes a structure and I have an array.

If this is not possible purely in ColdFusion, is it possible in Java somehow (maybe using Arrays.sort(Object[], Comparator))?

Answer 1

Here is something that closely resembles the original StructSort(). It also supports the pathToSubElement argument.

<cffunction name="ArrayOfStructSort" returntype="array" access="public" output="no">
  <cfargument name="base" type="array" required="yes" />
  <cfargument name="sortType" type="string" required="no" default="text" />
  <cfargument name="sortOrder" type="string" required="no" default="ASC" />
  <cfargument name="pathToSubElement" type="string" required="no" default="" />

  <cfset var tmpStruct = StructNew()>
  <cfset var returnVal = ArrayNew(1)>
  <cfset var i = 0>
  <cfset var keys = "">

  <cfloop from="1" to="#ArrayLen(base)#" index="i">
    <cfset tmpStruct[i] = base[i]>
  </cfloop>

  <cfset keys = StructSort(tmpStruct, sortType, sortOrder, pathToSubElement)>

  <cfloop from="1" to="#ArrayLen(keys)#" index="i">
    <cfset returnVal[i] = tmpStruct[keys[i]]>
  </cfloop>

  <cfreturn returnVal>
</cffunction>

Usage / test:

<cfscript> 
  arr = ArrayNew(1);

  for (i = 1; i lte 5; i = i + 1) {
    s = StructNew();
    s.a.b = 6 - i;
    ArrayAppend(arr, s);
  }
</cfscript> 

<cfset sorted = ArrayOfStructSort(arr, "numeric", "asc", "a.b")>

<table><tr>
  <td><cfdump var="#arr#"></td>
  <td><cfdump var="#sorted#"></td>
</tr></table>

Result: