How can I create a matrix or cell array for a changing condition?

Hi,

I have an irregularly spaced time vector and I would like to create a matrix or cell array with the first column holding all values between 0-6 seconds and the 2nd column 6-12 etc. Im pretty sure there is an easy solution but I am new to matlab and cant find one.

Below is the code I have so far, the result is a matirx which seems to do most of what Im asking but only displaying the first value for each condition.

Any help would be greatly appreciated.

Ben

    Cycles = 2
    
    % Vector with irregularly spaced time values 
    sig_time = [0 0.21 1.83 2.91 2.93 4.04 5.38 5.65 6.89 7.22 7.54 8.62 9.11 9.87 10.02 10.56 11.88 12]'
    
    % Creating Empty Sigma Matrix
    Sig_Vec=NaN(length(sig_time),Cycles);
    
    Period = 0;
    i=1;
    % Seperating Sigma By Cycles
    for ii = 1:length(sig_time)
        if (Period<=sig_time(ii) && sig_time(ii)<=Period+6)
        Sig_Vec(ii,i)=(sig_time(ii));
        Period=Period+6;
        i=i+1;
        end
    end  
    
% Result 
  0	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	6.89
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN
NaN	NaN

Answer 1

[Tommy]

Rather than looping through each value in sig_time, loop through the cycles (i.e. array columns):

Period = 0;
for i = 1:Cycles
    subset = sig_time(Period <= sig_time & sig_time < Period+6); % all values in sig_time between Period and Period+6
    Sig_Vec(1:length(subset),i) = subset;
    Period = Period+6;
end

You may prefer to go with the cell array so you don't have to deal with the NaN values:

Sig_Vec = cell(1,Cycles);

Period = 0;
for i = 1:Cycles
    Sig_Vec{i} = sig_time(Period <= sig_time & sig_time < Period+6);
    Period = Period+6;
end

but of course that means you have to deal with cells.

[Ben Mound]

Hi Tommy,

Really appreciate the reply, that worked perfectly and saved me a lot of agro! Thank you very much.

Kind reagards,

Ben