It is being updated: it is having the previous value(s) removed from it and the new value is being stored in it, every iteration of the loop.
What you probably want is to initialize the array once before the loop instead of initializing it in every iteration of the loop. For example,
eWithNoChange = [];
for clock = 0:0.999
eWithNoChange(end+1) = e;
end
Side note:
When you have a for loop, after the loop is finished executing, the index variable (such as clock) is left as the last value that was assigned to it. For example,
for I = 1 : 10
disp(I);
end
then since 10 was the last value assigned to I, after the loop, I will be left as the value 10 .
