Empty Global Array

I'm not really sure what the best way to declare global or public variables is, but I've declared a public array in a module as shown in the picture below. However, when my sub is executed, it says my public array "Pattern" is empty. What am I doing wrong?

excel.png

Originally Posted by xladept

[...]it should be a Variant rather than a String.

It appears that String is an appropriate type to use in this case. Every element of the array is a String.

Originally Posted by shg

You can't declare a variable as public in a procedure -- your code doesn't compile. It needs to go at the top of the module:

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Also, the default lower bound of an array is 0, not 1. You should declare bounds explicitly.

I've reserved 0 as a non-match for a pattern in a sub, so that's the reason why it's not declared. Are you saying that I should avoid declaring bounds like this:

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and instead, do this:

For i = 2 To 12

Originally Posted by 6StringJazzer

You are confusing the concept of global variables vs. public variables. Before I start explaining, they should both be used sparingly. You also have a problem with variable declarations.

I strongly recommend to everyone that they declare variables. Doing so prevents a lot of bug and runtime errors. In your case, you are not using Option Explicit so if you use a variable without declaring it, VBA will not tell you it's an error--it just assumes you meant to declare it, and it declares it for you with a type of Variant. I'll come back to that in a minute.

A global variable is one that has scope and extant through an entire module. That is, it can be referenced by code anywhere in that module and its value is preserved throughout execution. (There is an exception to this called hiding that I'm not going to get into.) A global variable must be declared at the top of a module, before the first Sub. There is no keyword for global; if it declared at the top of the module, it is global.

A public variable is a global variable that has scope and extant through all modules. A Public variable is also global, and so must be declared at the top of a module, before the first Sub.

Your variable Pattern has been declared as Public, but you declared it inside a Sub. If you move your declaration to the top of the module, it will fix this.

Also, the place you use Pattern does not use Option Explicit. VBA does not see a declaration anywhere for Pattern that is in scope for where you are using it, so it simply creates a new variable for you and assumes it to be type Variant. This variable Pattern is a different variable than the Pattern you declared in Sub DeclareGlobalVariables. Because this new variable that has been so conveniently created has never received a value, you get a message that it's empty.

Thanks for the clear explanation. One other thing I'm curious about is that my primary sub is under a worksheet... should this sub be placed within a module underneath the global variable declaration instead of it being a worksheet module?

Originally Posted by shg

You can't declare a variable as public in a procedure -- your code doesn't compile. It needs to go at the top of the module:

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Also, the default lower bound of an array is 0, not 1. You should declare bounds explicitly.

Ok, I see. I missed your part about declaring the size of the array explicitly.

It looks like what I'm trying to do won't work with VBA anyway. I wanted to declare and initialize the array elements to be used in other subs or functions, but I get a compile error for invalid outside procedure.

Originally Posted by shg

That's why you put the initialization inside a procedure. Run Init first.

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Ok, cool. So, I can put the initialization inside a separate sub and then call that sub within another sub.