Vectorise for loop checking for values in intervals

Hi there,

I have the following datasets:

a =

     5
     7
     8
     9
    10
    12

b =

       3     6
      11    13
      20    22

I want to look if each element of a is in any of the intervals in b, without a for-loop. The for loop is:

result = zeros(length(a),1);
for i =1:length(a)
    for j= 1:size(b,1)
        if a(i)>=b(j,1) && a(i)<= b(j,2)
        result(i) = 1
        break;
        end
    end
end

I am hoping to speed this up.

Answer 1

[Guillaume]

If using R2016b or later:

result = any(a >= b(:, 1).' & a <= b(:, 2).', 2)

Otherwise

result = any(bsxfun(@ge, a, b(:, 1).') & bxfun(@le, a, b(:, 2).'), 2)

[TJ]

Works great. Thank you!