[Help-glpk] pick element from set?

[Kevin Hunter]

Hello GLPK List,

Is there a method to pick an arbitrary single item from a set?  I don't 
care which one, but I need to have a single element from a set such that 
I can uniquely and consistently identify it.

There is no order to the set, but /if/ there were an ordering to this 
set, I might reference this element as "nought".  Put differently, say I 
have a set X:

set X, dimen 2 := {(5, 7), (1, 10), (23, -3), ("y", "x"), ("a", "abc")};

Is there functionality -- say a function called "pick()" -- to pick an 
arbitrary element from that set?

Put another way, /if/ I could put that set into a list:

list(X) == [(5, 7), (1, 10), (23, -3), ("y", "x"), ("a", "abc")]

then I could get an arbitrary element, perhaps like 'get(list(X), 0)'.

Is there a method to grab a single element from the set?

I'll point out that I have an ad-hoc method of this for a 
single-dimensional set (using a nested setof structure and a comparison 
operator), but can't do it for any higher-dimensionality sets.

Thanks,

Kevin