Apple - Emulating associative arrays in AppleScript

Although AppleScript does have associative arrays, they are called "records". I tried using AppleScript records to give you a solution. In the code below, I was unable to use a string as a key. I did manage to use something that resembles a file name, an identifier, but this isn't really working. It's an idea of how to use an associate array in AppleScript though:

set theAssociativeArray to {|file name 3.jpg|:{width:400}, |file name 1.jpg|:{width:222}}

-- looking things up by key in an AppleScript record, which is really a dictionary, is fast
try
    get |file name3.jpg| of theAssociativeArray
    say "file name 3 is on list"
on error
    say "file name 3 is not on list"
end try
try
    get |file name 1.jpg| of theAssociativeArray
    say "file name 1 is on list"
on error
    say "file name 1 is not on list"
end try

I saw that in your example code, you defined lists of records. What I tried to do is to define records of records.

I think that the main thing to keep in mind about the strengths and weaknesses of AppleScript is that is a language designed for Interapplication Communication (IAC), revolving a round the "tell command" to tell different apps to get data, set data, and to control the apps by telling them commands.

Here is a link to an answer that I believe is relevant to an AppleScript solution for you:

Finding the Intersection of Two Lists

The ultimate solution using AppleScript would be to use AppleScriptObjC which would allow you to use Objective-C classes such as NSDictionary that are very much like associative arrays.

If you can use a shell script (or do shell script), awk supports associative arrays with string keys and fast lookup.

$ cat widths.txt
2.tif 600
1.tif 500
4.tif 700
$ cat heights.txt
4.tif 1000
2.tif 900
$ awk 'NR==FNR{a[$1]=$2;next}{print $1" "a[$1]/$2}' widths.txt heights.txt
2.tif 0.666667
4.tif 0.7