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Check for existing array element

Arrays

Check for existing array element

by  TruthInSatire  Posted    (Edited  )
The built in function isDefined() can not test arrays. Attempting a test will produce an error.

isdefined("myArray[1]")
produces
[quote error]
Parameter 1 of function IsDefined, which is now "myArray[1]", must be a syntactically valid variable name.
[/quote]

In order to test for the existance of an array element this UDF should do the trick.

USE: isArrayElementDefined("myArray[element]")
(This function also works for multi-dimensional arrays)
Code: 
[b]<cfscript>[/b]
    [color gray]//define the function[/color]
    [b]function isArrayElementDefined(arrayName){[/b]
          [color gray]//use try{} to attempt using the array element[/color]
          [b]try{[/b]
            [color gray]//use the array element and return true[/color]
            [b]testVar = evaluate(arrayName);
            return true;[/b]
          [color gray]//if using it causes an error catch it and return false[/color]
          [b]}catch(any test){
            return false;
        }
    }
</cfscript>[/b]

EXAMPLE:
Code: 
<cfset myArray = arrayNew(1)>
<cfset myArray[1] = "bob">
<cfset myArray[3] = "joe">
<cfoutput>
<cfloop from = "1" to = "3" index = "place">
#isArrayElementDefined("myArray[#place#]")#
</cfloop>
</cfoutput>
OUTPUT: true false true
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