Grabbing the position of a value in an array

Okay, what I want is kinda hard to explain, so bear with me.

If I have an array:

myPets = ["cat", "dog", "bird", "fish"];

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Now, is there any AS that can use the value of say “dog”, and return the position that “dog” is in the array, I know this seems a bit stupid and dog is obviously myPets[1], but when I’m creating arrays on the fly it becomes slightly harder.[/font]