How can I assign a variable to all the columns and all the rows of a matrix?

48 views (last 30 days)
Got a 20x10 double matrix and I'd like to assign 'numsub' to the number of rows and 'numtrials' to the number of columns in the whole matrix so that I can use them as an index in a for loop for extracting values from certain subjects.
I will need to do something like this:
for i = 1:numsubs
disp(['sub' num2str(i)])
disp('Slow trial')
for j=1:numtrials
if RT(j,i)<=0.3
disp(['trial' num2str(j)])
end(x3)

Accepted Answer

Jos (10584)
Jos (10584) on 23 Oct 2019
Are you looking for the function SIZE?
data = rand(20,10) ;
[numsubs, numtrials] = size(data)

More Answers (1)

Bob Thompson
Bob Thompson on 23 Oct 2019
You don't need to actually create a new variable for this, you can just use the results from size.
A = randi(100,20,10);
[r,c] = size(A); % Where r is the number of rows, and c is the number of columns
% You can also just put the function directly into your loop
for i = 1:size(A,1)
...
for j = 1:size(A,2)
...
end
end

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by