Only applying a "for" command on half of the matrices in it
3 views (last 30 days)
Show older comments
Filip Hansson
on 15 Aug 2022
Commented: Image Analyst
on 16 Aug 2022
I have a "for" command that makes certain elements in about 60 matrices to a constant. I would like to make it so every time I run the script the "for" only selects a random 30 matrices to make that change and for the ramaining 30 to be left unchanged. How is this possible??
The code at the moment:
for i = 11
m_a(m_spotpris==1) = i;
m_b(m_spotpris==1) = i;
m_c(m_spotpris==1) = i;
m_d(m_spotpris==1) = i;
.
.
.
% And so on
0 Comments
Accepted Answer
Image Analyst
on 15 Aug 2022
You need to make m an array, not 60 separately named variables.
2 Comments
Image Analyst
on 16 Aug 2022
Did you try a simple for loop:
% Thank you! I have done this and is now stuck with the same problem.
% I have a 24x364x60 array and would like to set 4 of those 24 values to 11,
% based on another matrix with "1"s in those particular positions,
% for 30 randomized of those 60 arrays. How is this possible?
% Assign sample data.
array3d = randi(99, 24, 364, 60);
[rows, columns, slices] = size(array3d)
refMatrix = randi([0, 2], 364, 60);
% Get 4 randomly chosen rows.
rowsToChange = sort(randperm(rows, 4))
% Replace array3d where refMatrix is 1.
for k = 1 : length(rowsToChange)
thisRow = rowsToChange(k);
for col = 1 : columns
for slice = 1 : slices
if refMatrix(col, slice) == 1
array3d(thisRow, col, slice) = 11;
end
end
end
end
More Answers (1)
David Hill
on 15 Aug 2022
m=randi(10,10,10,60);%generate your matrix (should store as 3-D matrix)
r=randperm(60,30);%generate the 30 affected matrices
for k=1:length(r)
M=m(:,:,r(k));%establish temp matrix
M(M==1)=99;%change all of the 30 affected matrices where elements equal 1 to 99
m(:,:,r(k))=M;
end
0 Comments
See Also
Categories
Find more on Data Type Conversion 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!