finding duplicate number and adjacent row value

Suppose I have a matrix of values

v = [1 4; 1 5; 2 4; 2 4; 2 5; 2 5; 3 4; 3 7]

in column one the numbers are consecutive but with repetition, how can I find only the first numbers and corresponidng number in the other column, put them in a new matrix (v')? The new matrix should be like this from my example:

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

I hope I am clear enough

Cheers

Sobhan

[Azzi Abdelmalek]

what if v= [1 4; 1 5; 2 4; 2 4; 2 5; 2 5; 3 4; 3 7;1 5;1 6]?

Answer 1

[Azzi Abdelmalek]

v = [1 4; 1 5; 2 4; 2 4; 2 5; 2 5; 3 4; 3 7]
idx=diff(v(:,1))
v1=[];
if idx(1)==0
  v1=[v1;v(1,:)]
end      
for k=2:length(idx)
  if idx(k)==0 & idx(k-1)~=0
    v1=[v1; v(k,:)]
  end
end

[Sobhan]

Dear Azzi, your solution worked perfectly! Thanks a lot. Wayne`s method gave an error. Anyhow, thanks a lot to both of you

Answer 2

[Wayne King]

[~,iv] = unique(v(:,1),'stable');
vnew = v(iv,:);