How do I find values close to a given value?

Question

I have data = [1 1.2 1.3 1.5 1.8]

I want to find closest values before and after from data for this point, b = 1.23

How do I do th

Answer 1

if the data is sorted you can use find:

i_lower  = find(data <= b,1,'last');
i_higher = find(data >= b,1,'first');

lower_than_b  = data(i_lower)
higher_than_b = data(i_higher)