how to obtain the id of change in vector

i have a vector say

v =[ 0 0 0 0 28 34 0 56 67 0 0 0 69 71 75 89 90 0]

I need to find what are the ids where there is change in value from 0 to some number or from some number to 0. So in this case the ids should be like 5 6 8 9 13 17

Is there a smart way to do it?

Answer 1

[Walter Roberson]

Lv = (v ~= 0);

find( Lv(1:end-1) ~= Lv(2:end) )

[Niraj]

Thanks for the reply. but it gives the output as : 4 6 7 9 12 17

but i need

5 6 8 9 13 17

I will play around with the functions.I thought there is some special function in MATLAB. I know that nnz is a function to find the total number of changes in a vector, but wanted to know if there is any function which gives the id of the change as well.

[Jan]

I assume "id" means "index".

[Niraj]

yes,"id" means "index".

Answer 2

[Jan]

Lv = (v ~= 0);
Index = find(diff(Lv)) + 1;

[EDITED]

Lv    = [false, (v ~= 0), false];
ini   = strfind(Lv, [false, true]) + 1;
fin   = strfind(Lv, [true,  false]);
Index = reshape([ini(:), fin(:)], 1, []);

[Niraj]

Thanks for the answer, but it gives the output as

5 7 8 10 13 18

but i want

5 6 8 9 13 17

[Jan]

See [EDITED]