Thursday, 27 September 2012

Variables as lists

I think you'd be hard pushed to find a Uniface developer that didn't know that a string variable can be used to hold a list of values.  The Uniface list construct uses a gold-semi-colon as the list delimiter, denoted in the manuals as ; but in code looks like ·; - for example...

  s = "27/Sep/2012·;28/Sep/2012·;29/Sep/2012"

I spent quite a long time today trying to work out why such a simple thing was not working for me.  It took quite a long time for me to realise that I'd accidentally declared (or rather, re-used) a numeric variable.  This gives a rather different result...

  n = "27/Sep/2012·;28/Sep/2012·;29/Sep/2012"

I wasn't previous aware that a numeric variable could hold a list in this way, but it's handy to know! 

The same also works with dates...

  d = "27/Sep/2012·;28/Sep/2012·;29/Sep/2012"

Take a look at this screenshot to see the results...

I'm not going to go through all the data types to confirm which ones it works with, but I suspect it would work with all of the simple ones (such as datetime and float) but not with the more complex ones (such as handle and occurrence).

Summary: It's not just string variables that can be used to hold lists; numeric and date variables also can, along with many others I suspect.

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