Split a matrix into a two submatrixes by a condition

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Gino Franco
Gino Franco 2014-10-2
编辑： Mohammad Abouali 2014-10-7
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.

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采纳的回答

Mohammad Abouali
Mohammad Abouali 2014-10-2
编辑：Mohammad Abouali 2014-10-2
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.

更多回答（1 个）

Iain
Iain 2014-10-2
This is the "simple" answer:
male = ex3(find(ex3(:,1) == 1),:);
female = ex3(find(ex3(:,1) == 0),:);

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