for loop saving a vector, not a value

Question

soloby 2015-6-13

评论： Image Analyst 2015-6-13

if i had

x = -10:0.1:10;
f1 = trapmf(x,[-2 0 0 2]);

how do i save the (x, f1) values of each iterations using the for loop?

I'm thinking it starts with something like

for 
    i = 1:length(x)
    a = x(i);
    b = f1(i);
end

but this will only give me a & b to be 1 value not a vector of length(x)

Answer 1

Image Analyst 2015-6-13

How about

for i = 1:length(x)
      a(i) = x(i);
      b(i) = f1(i);
end

if you wanted/needed to assign a and b via a "for" loop?

soloby 2015-6-13

that works. but i guess that's an unnecessary step since x and f1 are already the same thing.

Do you know of a way to divide my f1 function, which is a triangular wave, into 2 parts: values left of the peak and right of the peak?

thanks in advance.

Image Analyst 2015-6-13

I don't see why you say "x and f1 are already the same thing" but I don't have the fuzzy toolbox so I can't actually run trapmf().

To divide into two parts

[maxValue, indexAtMax] = max(b);
leftOfPeak = b(1 : indexAtMax-1);
rightOfPeak = b(indexAtMax+1 : end);

Note that the peak itself is not included in either of those arrays because you did not specify that it should be.