How to access an individual column from data
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Hi guys, this might be a simple question but i don't really know how to do it.
I have 10x8 matrix, and want to specify every column besides the first one as: x1,x2,x3,x4,x5,x6,x7. Like, x1 = [...], x2 =[...] etc. Until now i've done it manually by copy-paste the values, but i'm sure there is a much easier way.
Thanks, B!
2 Commenti
Stephen23
il 28 Nov 2017
"...i'm sure there is a much easier way."
Yes, there is: use indexing. Indexing is simple, neat, and very efficient. Do NOT magically create or access variable names in a loop:
Risposte (2)
KSSV
il 28 Nov 2017
It is not required to name each column by x1, x2....x10.....it is waste of time and not all necessary. Already you have all the data in a matrix form..this is sufficient.
A = rand(10,8) ; % matrix
A(:,1) % gives first column
A(:,7) % gives seventh column
A(:,end) % gives last column ie eight
5 Commenti
Stephen23
il 28 Nov 2017
Modificato: Stephen23
il 28 Nov 2017
If mat is your matrix, then something like this:
mat = [...];
out = [...];
for k = 1:size(M,2)
vec = mat(:,k);
... do whatever with vec
out(k) = ... save the output
end
You will need to figure out the require size of the output matrix.
Note that basic MATLAB concepts, such as how to write loops and access data using indexing, are introduced in the introductory tutorials. These tutorials are highly recommended for all beginners:
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