gistfile1.txt

<cfset aItemsToDeleteTemp = [{"id"="apples"},{"id"="oranges"},{"id"="bananas"},{"id"="pears"},{"id"="kiwi"},{"id"=["peach"]}] />
<cfset aItemsInDB = [{"id"="apples"},{"id"="oranges"},{"id"="bananas"},{"id"="peach"}] />
<!--- Find the difference --->
<cfset aItemsToDeleteTemp.removeAll(aItemsInDB) />

<!--- Convert the remaining array of structs to a simple array --->
<cfset aItemsToDelete = [] />
<cfset aLen = arrayLen(aItemsToDeleteTemp) />
<cfloop from="1" to="#aLen#" index="r">
	<cfif isArray(aItemsToDeleteTemp[r]["id"]) is true>
		<!--- Due to a bug in CF, we have to do a nested cfif instead of both conditions in the same statement --->
		<cfif arrayFind(aItemsInDB,{"id"=aItemsToDeleteTemp[r]["id"][1]}) eq 0>
			<cfset arrayAppend(aItemsToDelete, aItemsToDeleteTemp[r]["id"][1]) />
		</cfif>
	<cfelse>
		<cfset arrayAppend(aItemsToDelete, aItemsToDeleteTemp[r]["id"]) />
	</cfif>
</cfloop>

<cfdump var="#aItemsToDelete#" abort="true" />