MATLAB: How could I cut a matrix into subgroups

cutgroupsegment

How could I cut a matrix into several small groups according to the 1st column, and I don't know how many subgroups I may get and the size of the subgroups are not the same(rows).
Say I have a matrix,
1 23 34
1 2 3
3 45 76
3 5 66
3 2 7
3 23 32
4 2 2
4 5 27
4 1 0 ….
And finally, I would like to get :
1 23 34
1 2 3
and
3 45 76
3 5 66
3 2 7
3 23 32
and
4 2 2
4 5 27
4 1 0
and …
How could I do that? Thanks in advance!

Best Answer

[sz] = histc(X(:,1),unique(X(:,1))); %X is your matrix
C = mat2cell(X,sz,size(X,2)) %each cell will contain one matrix
This is tuned to work assuming column one is sorted if it's not:
X = sortrows(X,1);
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