Count specific values in a matrix and Find row and column number of the first value among consecutive same values.

1) Counting the number of the specific values. such as

[1 1 1 1 1 1 2 2 2 2 3 3 3 3 3 4 4 4 4 4 4 4 4 4 5 5 5 6 6 6 6 6 6 6 6 7 7 7 8 8 8 8 8 ....]

=> result [ 6 4 5 ....]

2) Call the first row and column number of a specific value.

 the first '2' value is [row column] = [1 7]

Answer 1

[Andrei Bobrov]

s = [1 1 1 1 1 1 2 2 2 2 3 3 3 3 3 4 4 4 4 4 4 4 4 4 5 5 5 6 6 6 6 6 6 6 6 7 7 7 8 8 8 8 8];

1)

t = [true,diff(s)~=0];
[ii,jj]=find(t);
result = diff([jj,numel(s)+1]);

2)

out = [s(t);ii;jj]';