How can I split measured data in separate vectors, depending on sign value?

Hello! Is it possible to split measured data f.e.v= [1 2 3 4 5 4 3 2 1 2 3 4 5 4 3 2 1] in separate vectors, f.e. only the 'growing' values: v1=[1 2 3 4 5], v2=[1 2 3 4 5].

Maybe with a find(sign(diff(v))==1) ?

Thank you!

Answer 1

[Star Strider]

One approach —

v= [1 2 3 4 5 4 3 2 1 2 3 4 5 4 3 2 1];
dv = gradient(v);
sel = v(dv>=0);
dsel = diff([1 find(diff([sel(1) sel])<0) numel(sel)+1]);
C = mat2cell(sel, size(sel,1), dsel)

C = 1×2 cell array
    {[1 2 3 4 5]}    {[1 2 3 4 5]}

v1 = C{1}

v1 = 1×5

1 2 3 4 5

v2 = C{2}

v2 = 1×5

1 2 3 4 5

.

[Anna B.]

Thank you very much for the quiсk response. I have tried both variants and it works perfectly!

[Star Strider]

As always, my pleasure!

Answer 2

[Jan]

Start with a simple loop approach:

v  = [1 2 3 4 5 4 3 2 1 2 3 4 5 4 3 2 1];

dv  = [false, diff(v) > 0, false];
ini = strfind(dv, [false, true]);
fin = strfind(dv, [true, false]);
C   = cell(1, numel(ini));
for iC = 1:numel(ini)
   C{iC} = v(ini(iC):fin(iC));
end
C

C = 1×2 cell array
    {[1 2 3 4 5]}    {[1 2 3 4 5]}

[Anna B.]

Thank you very much for the quick response. I have tried both variants and it works perfectly!