find data in array

hi, according to an answer header = fread(ropaRadarReceive,bytesToRead);

where = find(header == 53);
if ~isempty(where)   
     %at least one 53 found
     nextbytes = header(where + 1);  %note that if more than one 53 is found, nextbytes will be a vector
     %...
end

now I have found 53, that header can be followed by 0 or 1 or 2 or 3, OR normal bytes other than those values.

I want to test if the next byte of 53 is 0 or 1 or 2 or 3, if that's true, I want to get the bytes after 0 or 1 or 2 or 3. UNTILL the next header is found which is 53.

Please help me

Answer 1

[Ameer Hamza]

If more then one 53 are found then where will be a vector and you need to use it like this

nextbytes = header(where(1)+1:where(2)-1);

[Ahmed Tolba]

and how do I get the data after 53 is found and check if the next byte is 0, then get the data after 0 till the next 53 ? Thanks for your answer

[Ameer Hamza]

Try this

if numel(where) > 1 & header(where(1)+1) == 0 % check if there are more then 1 53s and number after first 53 is 0.
  nextbytes = header(where(1)+2:where(2)-1);
end

[Ahmed Tolba]

I need after byte 0 is found to get the data after it till the next 53

[Ameer Hamza]

If you can give an example of your data, then it will be easier to suggest a solution.

[Ahmed Tolba]

53 0 1 2 3 4 5 6 7 8 9 53 1 24 59 5 95 95 53 2 59 58 575 75 53 0..etc

[Ahmed Tolba]

I provided data

[Ahmed Tolba]

I would like the next bytes after 0 and before the next 53

Answer 2

[Andrei Bobrov]

i1 = find(header(:)==53);
p = hankel(header(1:end-1),header(end-1:end));
i2 = find(ismember(p,[53*ones(4,1),(0:3)'],'rows'));
[~,aa] = setdiff(i1,i2); 
i1 = i1(aa) + 1;
i2 = i2 + 2;
out = header(sort([i1(i1 < numel(header));i2(i2 < numel(header))]));

use

>> header = [53 0 1 2 3 4 5 6 7 8 9 53 1 24 59 5 95 95 53 2 59 58 575 75 53 0]
header =
  Columns 1 through 18
    53     0     1     2     3     4     5     6     7     8     9    53     1    24    59     5    95    95
  Columns 19 through 26
    53     2    59    58   575    75    53     0
>> i1 = find(header(:)==53);
p = hankel(header(1:end-1),header(end-1:end));
i2 = find(ismember(p,[53*ones(4,1),(0:3)'],'rows'));
[~,aa] = setdiff(i1,i2); 
i2 = i2 + 2;
out = header(sort([i1(aa)+1;i2(i2 < numel(header))]))
out =
     1    24    59
>>

[Ahmed Tolba]

I would like the next bytes after 0 and before the next 53