How to delete element from a vector in the beginning and last part of my signal

Hi everybody, I'm trying to find a way to cut my signals (in the initial and final part). I've found something that works for my main vector but then, when I try to cut other vector in the same way using the indexes I get some problems. That's the code that I'm using:

Stress1= Stress(1:40,:);

Stress2= Stress(41:end,:);

goodIndexes = Stress1 <10 & Stress1>0 ; 

goodSignal = Stress(goodIndexes);

goodIndexes2= Stress2 > 5;

goodSignal2= Stress2(goodIndexes2);

Stress_fin= vertcat(goodSignal, goodSignal2);

Disp_1= Displacement (goodIndexes);

*Disp_2= Displacement (goodIndexes2);*

Disp_fin= vertcat (Disp_1, Disp_2);

Force_1= Force (goodIndexes);

*Force_2= Force (goodIndexes2);*

Force_fin= vertcat (Force_1, Force_2);

Eyy_1= Eyy (goodIndexes);

*Eyy_2= Eyy (goodIndexes2);*

Eyy_fin= vertcat (Eyy_1, Eyy_2);

While I obtain what I want for the "Stress" vector, I'm not able to get the same result for the other three vectors because the second vector of each other signal ( Displacement_2, Eyy_2, Force_2) restart from the first index of the father vector and not fromt the index "41" and so I can't get what I want.

Any advice to overcome that problem?

Thanks in advance.

Danilo

Answer 1

[Guillaume]

Note: A good way to find out what is going wrong with your code is to use the debugger and closely watch how your variables evolve as you step through each line.

Yes, clearly your code is not going to work. You split your stress vector into 2, Stress1 is indices 1 to 41 (hence length 41) and Stress2 is indices 42 to end (length unknown, let's call it x, its value does not matter).

You then filter these 2 vectors and obtain two logical vectors of length 42 and x which you use to filter the split vectors. So that works fine

But you also use the logical vectors to filter the complete displacement and force vector. Hence with your first logical vector, you're filtering the first 41 elements, with your second you're filtering the first x elements. In each case, you're filtering from the start. The solution is to concatenate your logical vectors:

Stress1= Stress(1:40,:);
Stress2= Stress(41:end,:);
goodIndexes1 = Stress1 <10 & Stress1>0 ; 
goodIndexes2 = Stress2 > 5;
goodIndexes = [goodIndexes1; goodIndexes2];  %concatenate the two logical vectors

Stress_fin = Stress(goodIndexes);
Disp_fin = Displacement(goodIndexes);
Force_fin = Force (goodIndexes);
Eyy_fin = Eyy(goodIndexes);

[Danilo Ambrosio]

Thank you! I didn't know how to concatenate the vectors.

Answer 2

[KSSV]

vec = rand(!00,1) ;    % be your vector/ signal 
vec(1)=  [] ;     % removes the beginning i.e the first element
vec(end) = [] ;   % removes the end i.e the last element