How do I predefine a variable?

I have predefined the variable:

no_of_zeros = cell(1,54);

however when I run my code it says:

'Index exceeds matrix dimensions.

Error in testrun (line 32) no_of_zeros = size(mydata{i,1},5) - nnz(mydata{i,1}(:,5)); %number of zeros'

My script following the pre defined varaible is:

for i=1:length(mydata)
      no_of_zeros = size(mydata{i,1},1) - nnz(mydata{i,1}(:,5)); %number of zeros
      no_of_frames = (no_of_zeros/4) % number of frames 
      time = ((no_of_frames/fps)/2) % time up
      jumph(i,1)=((a*(t*t))/2) % jump height
end

Where am I going wrong?

Answer 1

[hossein]

In the first line of your for loop, you're referring to the fifth character of the cell mydata{i,1}. Is it possible that the cell you're referring to doesn't have enough characters? Also, no_of_zeros is scalar (it's size is 1), so you don't need to pre-define it. Just make sure "nnz(mydata{i,1}(:,5))" doesn't produce an error.

[Franchesca]

The 5th character? I thought I was referring to the 5th column to count the number of zeros in that column?