Monday, October 1, 2007

Simplifying Evaluate

If you're only interested in getting a single value from Evaluate, you don't need to Dim a Variant to containt the Array Evaluate (almost) always returns.

Simply implode the evaluate, and you can assign the Evaluate directly.

Dim commonUsername As String
commonUsername = Implode( Evaluate( |@Name( [CN] ; @UserName )| ) )


Jake Howlett said...

Brilliant! I love tips like this and I hate dimming variants just to get one value.

J E Carter II said...

Very nice little trick, Tommy! Thanks for sharing!

Chris said...

I can't believe I never thought of that before. This has bugged me for years. I always wanted to do this instead:
Evaluate(|@Name([CN]; @UserName)|)(0)

Now I don't have to declare that useless temporary Variant variable anymore.


Nate said...

Nice one, Tommy!

I'm curious... why Implode instead of it's shorter alias Join?

Tommy Valand said...

I guess because of reading co-workers code, and being influenced by the formula-language, which @Implodes.

I think I'll try to change my habit, since, as one commenter on Codestore said, Join is three letters shorter than Implode, and split/join is also what those "operations" are called in JavaScript.

I also think split/join are better descriptions of what is goin on.

William Beh said...

Very very cool. Tried it out and started using it for application which is roll out to production.

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Anonymous said...

Does anyone know why this returns a empty string..?
Note it works if I replace s with "abcdefgh" in the actual evaluate...

Dim v as variant
Dim s as string

s = "abcdefgh"
v = Evaluate({@Middle(s; "B"; "H")})

msgbox v(0)

Should return "cdefg" but returns blank string?

Tommy Valand said...

Dim v as String
Dim s as String

s = "abcdefgh"
v = Join( Evaluate({@Middle("} + s + {"; "B"; "H")}) )

MsgBox v