Loop over array of structures and output specific struct value?

Question

I have array of structures where I should access specific field. Here is example of my data:

array
1   
   struct
   address_city     Washington
   address_state    DC
array
2   
   struct
   address_city     New York
   address_state    NY
array
3   
   struct
   address_city     Miami
   address_state    FL

I have this code to loop over array and then inner loop to iterate over structures:

<cfloop from="1" to="#arrayLen(arrData)#" index="i">
    <cfset data = arrData[i]>
    <cfloop collection="#data#" item="key">
        <cfoutput>#key#:#data[key]#<br></cfoutput>
    </cfloop> 
</cfloop>

Code above will produce this output:

address_city:Washington
address_state:DC
address_city:New York
address_state:NY
address_city:Miami
address_state:FL

Instead I need to access only address_state value. I have tried something like this:

<cfloop from="1" to="#arrayLen(arrData)#" index="i">
    <cfset data = arrData[i]>
    <cfloop collection="#data#" item="key">
        <cfoutput>#data[key]['address_state']#<br></cfoutput>
    </cfloop> 
</cfloop>

Then I was getting this error message:

Message     You have attempted to dereference a scalar variable of type class java.lang.String as a structure with members. 

Is there a way to output only one field from each structure in array? Something similar is doable in JavaScript when iterating over JS Object. Example:

for (var key in data) {
    console.log(data[key]['address_state']);
}

If anyone knows the way to achieve this in ColdFusion please let me know.

Answer 1

Funny enough, there is a way to do it almost exactly like the JS example.

for (key in data) {
    writeOutput( "Address State = " & key.address_state & "<br>");
}

https://trycf.com/gist/f0bd28bbf644912d320b10fdc5f526f4/acf?theme=monokai

You were getting the error because you were referencing the data array when you didn't need to. You were already looping through the keys in data by nature of your loop. In your script example, you didn't need to do a double loop through your array.