[Help-glpk] A couple of simply MathProg questions

[Harley Mackenzie]

I have a couple of pretty fundamental MathProg questions that seem simple but I 
cant find a solution in the manual:

Given a set:

set SB := SP1   SP2   SP3   SP4   SP5   SP6   SP7   SP8   SP9  SP10  SP11  SP12 
 SP13  SP14  SP15  SP16  SP17  SP18  SP19  SP20  SP21  SP22  SP23  SP24  SP25  
SP26  SP27  SP28  SP29  SP30  SP31  SP32  SP33  SP34  SP35  SP36  SP37  SP38  
SP39  SP40  SP41  SP42  SP43  SP44  SP45  SP46  SP47  SP48  SP49  SP50;

1. Is there an operator to tell me the number of symbols in the set. The only 
solution I have come up with is "sum {sb in SB} 1", but I think there may be a 
better way.

2. How do I write an iteration statement to sum all of the elements except the 
last one. Again the only solution I have come up with is: "sum {sb in SB: sb != 
'SP50'}" but this ties the model to a specific value "SP50" in the model and I 
want to vary the number of elements in SB so the terminal value "SP50" will 
change and the change is required in the model section not the data section. Is 
there a way of writing this without having to change the model for different 
numbers of elements in SB?

Thanks,

Harley
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