MATLAB: How to replace a number in an array with a different function

Question

I have a problem replacing certain values within an array that was created by a function with values that were created by another function.

My arrays looks like this:

v = xlsread ("Example");
i = [i_1;i_2;i_3];
n = (v.*60*i_1)/(2*pi*r);

and it creates a 1186×1 vector.

Now I want to recalculate all entries of this vector that are greater than 3000 with a new function that would be

n = (v.*60*i_2)/(2*pi*r);

So far I can only find all coloums with entries greater than 3000 and replace them with a constant value through

j = find (n_M_NEFZ > 3000);
n(n>3000)= 10;

but I cannot replace those values with values from the second function.

Answer 1

toreplace = n>3000;  %find is a waste of time. Use the logical array directly
n(toreplace) = v(toreplace)*60*i_2 / 2*pi*r;

Note that numbered variables (i_1, i_2, i_3) are indication of a bad design. You should index a vector instead (your i that you never use):

n(toreplace) = v(toreplace)*60*i(2) / 2*pi*r;