How can I separate similar values in an array?

For example:

A = [ 44 45 44 -19 -19 -19 -18 -19 45 43 10 11]

I want the result to be

A1 = [ 44 45 44 45 43]

A2 = [ -19 -19 -18 -19]

A3 = [ 10 11]

And I would need this to be able to create an unlimited number of groups (ie. A1, A2, A3, ... , An)

Please help

Answer 1

[Cedric]

You can use an approach based on the following:

 % - Define threshold (max diff. that doesn't break a group).
 threshold  = 5 ;

 % - Locate boundaries.
 boundaries = [true, abs(diff(A)) > threshold, true] ;

 % - Convert blocks -> cells.
 A_grp = mat2cell(A, 1, diff(find(boundaries))) ;

Here, A_grp is a cell array whose elements contain vectors that you named A1, A2, etc. For example:

 >> A_grp{1}       % What you named A1.
 ans =
    44    45    44

EDIT: I assumed that you could define a threshold manually; if it is not the case, jump directly to Image Analyst's answer.

[Arielle Clute]

Thank you so much, I am defining a threshold manually so your code works perfectly!

Answer 2

[Image Analyst]

You need an unsupervised clustering algorithm. Go here for a list of a bunch of clustering algorithms: http://en.wikipedia.org/wiki/Category:Data_clustering_algorithms. Or maybe you could use the mean shift algorithm.

[Arielle Clute]

Thank you!