fetching data from array

I have a set of values as

G=[1 1 1 1 2 2 1 2 3 2 2 1 3 3]

in this there are 14 values,i want to fetch as following

there are 4 ones continously so i want to take first 1 ,then 2 2's continously ,i need first 2 ,then only 1 ,so i need to take that

So the output will be [1 2 1 2 3 2 1 3] with index positions [1 5 7 8 9 10 12 13]

kindly help

Answer 1

[Andrei Bobrov]

G=[1 1 1 1 2 2 1 2 3 2 2 1 3 3];

G1 = G(:);
l = [true;diff(G1(:))~=0];
out = [G1(l),find(l)]

Answer 2

[Jan]

With: FEX: RunLength

[value, number, index] = RunLength(G)

Then value and index are the wanted results.

If you have problems to compile the fast MEX file, you can use RunLength_M from this submission instead. If you process millions of elements and runtime matters, be sure to use the compiled version.

[kash]

Thanks Jan for ur answer