Deletion of array value in both positions of separate arrays dependent upon the range of one array

Im trying to limit an array to within range -3 to 3 but also delete the corresponding value in another array if the value in the first array falls outside range.

A = [1 2 4];
f = [2 1 .1];
gamma = [0 pi/2 pi/4];
time = [0:0.1:10];
for i = 1:3  
        result = A(1,i)*cos(2*pi*f(1,i)*(time)+gamma(1,i));
        if result < 3 & result > -3
            plot(time, result); hold on;
        elseif result > 3
             delete time(1, i)
             delete result(1, i)
        elseif result < -3
             delete time(1, i)
             delete result(1, i)
        end

Answer 1

[Jos (10584)]

A few remarks:

1. what if result is exactly +3 or -3? (you might want to use <= rather than <)

2. replace the two ELSEIF's by a single ELSE, they have the same effect.

3. remove the values after the loop, by keeping track what to remove. In pseucocode:

RemoveMe = false(1,3)
for ...
    if ...
    else
       RemoveMe(i) = true ;
    end
end
time(RemoveMe) = [] 

4. you could remove the for-loop altogehte, using matlabs vectorisation capabilities

result = A.*cos(2*pi.*f.*time+gamma);
time(abs(result)>3) = []

5. maybe you do not want to remove the values but replace them with NaN, so all lengths etc stay the same

I hope this helps.

~ Jos

[Daniel James]

Well, im plotting the values of result against time, so if a value falls outside the range i want to remove both the sult and the corresponding time, im not sure how the plotting mechanism would behave if it read NaN.

[Jos (10584)]

Just try it:

x = 1:10
y = x.^2
y(7) = NaN
plot(x,y,'bo-')