I have a column of numbers,e.g.

0.12
0.13
0.18
0.25
0.30

They are each part of any array, i.e. y(1), y(2),...,y(5).

I want to find the closest number in this array to another number, say 0.15. I want to query each number until I get to the first number in the column that is greater than 0.15. Then I know that the correct value is the entry prior to that one.

Help is greatly appreciated.