loop indexing length of non zeroes

Hi, I'm trying to make a loop that finds the length of a sequence of numbers:

I want to find when x(:,4) is not equal to zero, and then find how long it's is the same number, I want to save the number and the start row, and the end row.

my output should look something like this:

Id    start    end    length
10    1320    1331    11
9     1352    1354    3

thanks for any help

[dpb]

See <FileExchange 41813 RunLength> from Jan. It'll return all the needed data to build your table. NB: There are 12 10s there, not 11...

[Morten Jørgensen]

thanks a lot

Is it possible to igore when there i zero?

[Adam Danz]

Have you tried the answer I proposed below? It ignores 0s as you described.

Answer 1

[Adam Danz]

Here are the steps needed to build your table.

% Create fake data that looks like your example
x = rand(2000,5);
x(:,4) = 0;
x(1320:1331,4) = 10;
x(1352:1354,4) = 9;

% calculate table components
isZero = x(:,4)==0;
dz = [0;diff(isZero)];
start = find(dz == -1);         %start column 
endIdx = find(dz == 1)-1;       %end column
ID = x(start,4);                %ID column
len = endIdx - start;           %Length column

% Create table
T = table(ID,start,endIdx,len,'VariableNames', {'Id','start','endIdx','length'});

Result

T =
  2×4 table
    Id    start    endIdx    length
    __    _____    ______    ______
    10    1320      1331       11  
     9    1352      1354        2  
    

* Note that 'end' is not a valid variable name nor a valid table column name.

Answer 2

[Steven Lord]

You can use the ischange function to identify abrupt changes in your data (the jump from 0 to 10 and the drop from 10 back down to 0.)