Logical Indexing: deleting empty array

I have trial names that end with numbers e.g. _1 or _30. The number suffix does not increment by _1, _2, _3 etc because I am only reading a few one minute trials over a thirty minutes of data. If the condition is 30 minutes, then the data from these trials is being stored in a 1x30 structure even though 2-29 is empty because I am only reading in two trials. Without changing the trial name, is there a way that only stores arrays that are populated?

tnum = str2num(fname(jtnum+1:j)); % trial number if there is one 

tnum(~cellfun(@isempty,tnum));%keeps only populated cells, I hope

%fname is the name of the trial which vary in length depending on the trial type e.g. condition_1. 

%tnum is the trial number e.g. 1, 2, etc 

%j is the length of the fname jtnum = j e.g. 14.

%here is how the data is being stored

if dtype{i} == 3% dtype is a signal and i one of many types of signals 

subj.(fname)(tnum).(datanames{i}) = M(:,i); % M is nxm input matrix 

end%dtype

The second tnum is the line where the error occurs:

<Input #2 expected to be a cell array, was double instead>

Therefore, I added a second line of code,

tnum = mat2cell(tnum)

but got an error saying <Matrix indices must be full double>

If I omit the second tnum, then the code works but I end up with something like this

subj.power_(2)
ans =

ana: []

force: []

but

subj.power_(1)
ans =

ana: [1x1 struct]

force: [1x1 struct]

So, it is these empty structures 2-29 that I want to get rid of and end up with a structure of 1xnumber of trials with data. Any suggestion of how to get rid of the empty array is appreciated.

Eric

[Azzi Abdelmalek]

Format your question http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

[Eric]

thanks for the suggestion

[Matt J]

Yet you chose not to follow it? It would be much easier to read your code if you applied the "{} Code" markup tool to it.

Answer 1

[Walter Roberson]

tnum(~cellfun(@isempty,tnum));%keeps only populated cells, I hope

doesn't do anything with its calculation. You need an assignment statement.

tnum = tnum(~cellfun(@isempty,tnum));%keeps only populated cells, I hope

[Eric]

I apologize for the typo. This line of code is written as:

tnum = tnum(~cellfun(@isempty,tnum));