Extracting every row from a matrix using a for loop
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I'm working with some velocity data and have a matrix 23,999x31.
I'm new to using Matlab, I'm able of extracting one row but would now like to be able to create a for loop that will allow me to extract each of the 23,999 rows in the matrix.
Any help for a Matlab novice would be greatly appreciated!
回答（1 个）
Rik
2021-10-15
This might not be optimal, depending on what you want to do, but the size function is here to help:
data=rand(23999,31)
for row=1:size(data,1)
rowdata=data(row,:);
%do something with that row here
end
4 个评论
Edward Keavney
2021-10-15
Yes, that is what this code does. You can see for yourself. I would recommend trying this with a small example:
data=(1:5).'+rand(5,2);% row x will have values x.####
for row=1:size(data,1)
rowdata=data(row,:);
fprintf('row %d contains:\n',row)
disp(rowdata)
end
See?
If you want to use the entire matrix at once, there is no need to index it at all. If what I showed isn't what you want, please given an example of what it is you want.
Edward Keavney
2021-10-15
You can do that with the code I already posted:
data=(1:5).'+rand(5,2);% row x will have values x.####
for row=1:size(data,1)
rowdata=data(row,:);
mean(rowdata) %you can store this in a vector
end
But it is better to use mean on the entire array:
mean(data,2) % specify the dimension to make it operate on the rows
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2021-10-15
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