Getting the Indices of an Array with conditions

i have a program in which i have a matrix (Let's say A) of 0's and 1's. The occurance of 0's and 1's are random I want to get the indeces information for example

A1= [- - - - - - - - - 15:30:00 15:30:01 15:30:02 15:30:03 15:30:04 15:30:05 15:30:06 15:30:07 - - - - 15:30:12 15:30:13 15:30:14 15:30:15 15:30:16 15:30:17 - - - - - - 15:30:24 15:30:25 15:30:26 15:30:27 - - 15:30:30 15:30:31 - - ];
A= [0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 1 1 0 0 ];
% i want the result vector to be like
B=[9 10 17 21 22 27 33 .....]

Conditions: 1. for all the zeros only one zero 2. for ones Starting and ending one

Or end result

B1= [0 15:30:00 15:30:07 0 15:30:12 15:30:17 0 15:30:24 15:30:27 0 15:30:30 15:30:31 0]

[Stephen23]

Neither A1 nor B1 are valid MATLAB syntax. Please provide actual variable definitions that we can use.

[Jan]

Please post working Matlab code. I cannot guess reliably, what

A1= [- - - - - - - - - 15:30:00 15:30:01 ...

is. A cell string? A string? A timeseries object, where - means a NaT?

The explanation "1. for all the zeros only one zero 2. for ones Starting and ending one" is not clear to me. Can you elaborate it a little bit? You mention two different wanted outputs:

B=[9 10 17 21 22 27 33 .....]
B1= [0 15:30:00 15:30:07 0 15:30:12 ...

What do you want exactly?

[Rik]

It looks like you should have a vector with true for each valid position and false for non-valid positions. Then you can use diff to find the alternation points and find the indices for your output.

Answer 1

[Jan]

A bold guess:

A   = [0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 0 0 1 1 0 0 ];
Ap  = [0, A, 0];  % Padding to care for leading and trailing 1s
ini = strfind(Ap, [0,1]);
fin = strfind(Ap, [1,0]);
B   = reshape([ini-1; ini; fin-1], 1, []);

[ARN]

I am sorry, i couldn't explain properly. This works Thanks