Split a matrix into a two submatrixes by a condition
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Gino Franco
on 2 Oct 2014
Edited: Mohammad Abouali
on 7 Oct 2014
Let "ex3" a matrix with an arbitrary length, which first column is gender (binary 0 or 1 for male o female), the second is age, the third is wage. How can I split this matrix into two submatrixes by gender using "for" and "if" functions? After that, i have to plot the wage versus the age, using plus sign (+) as a marker style for women and a circle (O) for men.
Anybody can give me an answer? I suppose that are few lines of code.
For the first part I've tried this:
for i=1:11
if ex3(i,1)==0
A=ex3(i,:)
else
B=ex3(i,:)
end
end
but this doesn't return me 2 matrixes, but a series of vectors.
2 Comments
Accepted Answer
Mohammad Abouali
on 2 Oct 2014
Edited: Mohammad Abouali
on 2 Oct 2014
If this is MATLAB programming class tell your teacher that using "for" and "if" is not necessary the correct way of learning matlab. Matlab has its own style of coding it's better to think that way. If it is a general programming class then the story is different.
So first the bad style MATLAB programming
female_ex3=[];
male_ex3=[];
for i=1:size(ex3,1)
if (ex3(i,1))==0)
male_ex3=[male_ex3;ex3(i,2:end)]; % Stripping of first column which tell you gender
else
female_ex3=[female_ex3;ex3(i,2:end)];
end
end
now a more accepted style in MATLAB
male_ex3=ex3( ex3(:,1)==0 , 2:end );
female_ex3=ex3( ex3(:,1)==1 , 2:end );
NOTE that I assumed 0 means male and 1 means female.
More Answers (1)
Iain
on 2 Oct 2014
This is the "simple" answer:
male = ex3(find(ex3(:,1) == 1),:);
female = ex3(find(ex3(:,1) == 0),:);
1 Comment
Mohammad Abouali
on 7 Oct 2014
Edited: Mohammad Abouali
on 7 Oct 2014
You don't even need find . Look at the two last line of code in my answer.
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