MATLAB: How to count the number of times a specific value appears within a range in a 1D vector

countindex

Given a 1D vector, x, that has 600000 elements, how can I count the number of times the value 1 appears after the 150th position (excluding 150)?

sum(x(151:end) == 1)

sum(x(2:end)==1 & x(1:end-1)~=1)

Assuming you intended to put spaces or commas between the numbers, use the sum function:

x=[3,7,2,9,4];
sum_x = sum(x)

produces:

sum_x =
      25