How do you calculate the size of an array?

[Photomofo]

Here's an array I'm using:

Dim Array (1 to 4, 1 to 400000, 1 to 12) as long

How big is this array? How big would it be as a double or string array?

 

[Photomofo]

Before I ask a question here I do 10 minutes to an hour of work looking for a solution. The key to finding a solution is asking the right question. Once I've asked a question here... in public... I find that I ask better questions and find my answer independently. It's funny how that works.

But then I'm also surprised nobody answered this question.

 

[joeu2004]

Obviously, it is 4*400000*12 = 19,200,000 elements.

If you want know how much memory, multiply by the number of bytes for each type: Byte, Integer, Long, Single, Double, Decimal, Currency.

Enter "type long" or whatever into VBA help, and the help page tells you the number bytes.

For fixed-length strings like String*12, I presume (but I don't know) that VBA allocates just that amount of memory (e.g. 12 bytes).

Variable-length strings and Variant are a different animal altogether. AFAIK, MSFT does not document the overhead that it allocates for those types. You might do a google search to see if someone else has figured it out.

It would be nice if VBA had a sizeof() function. AFAIK, it does not.

We might use VarPtr arithmetic in order to infer the size of such types. But I would need to experiment with it myself (I'm not going to) in order to determine the reliability and the issues with such calculations.