function for greatest object in list less than or equal to a value
hh
hh at livecode.org
Mon Oct 12 18:24:26 EDT 2015
[@Bernd: here a PONG to your PING.]
Obviously each list member has to be inspected once for the comparison.
And each "smaller than"-member has to be inspected once again to find
the maximum. There is no other way, this is a math fact.
Here is my solution, that seems to be pretty fast.
-- v is a real num, L is a list of real comma-delimites nums
-- if L has NO member < v then return MINVAL (=your setting)
-- Empty members are treated as 0 (doesn't harm, if all x>0)
-- Pre-sorting of L gives no advantage.
function greatestMemberSmallerThan v,L
put -10^15 into z[true] --> because max(empty)=0
repeat for each item x in L
-- if x is empty then next repeat --> here not necessary
put comma & x after z[x<v]
end repeat
return max( z[true] )
end greatestMemberSmallerThan
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