Matlab Array Formation From Data Set

I have an array of data e.g:

A = [300 10 1; 100 20 2; 100 30 4; 200 30 5;]

I would like to compile the third column data from in a new array as follows:

B = [1 0 0; 0 2 0; 0 4 5;]

where the X and Y 'scales' of array B are known and match the values found in columns 1 and 2 of array A:

X = [300 100 200]
Y = [10 20 30]

Any help is much appreciated,

Regards,

CS

[dpb]

1)

size(A)==[4,3] but size(B)==[3,3] ???

2)

Show/define the process by which you "scale" to get the values in B

I can make a reasonable fixup for 1) by presuming

A(3,:)=[];

to remove the third row. I can then make a first stab for 2) for

B(:,1)=fix(A(:,1)/X(1));

but I see no such similar relationship to the desired results shown for the other two columns...

[Guillaume]

What happens when two rows of A have got the same X and Y?

Answer 1

[Michael Haderlein]

Ha, got it:

X=[300 100 200];Y=[10 20 30];
A=[300 10 1;100 20 2;100 30 4;200 30 5];
[x,y]=meshgrid(X,Y)
[C,ia,ib]=intersect([x(:) y(:)],A(:,1:2),'rows')
B=zeros(length(Y),length(X));
B(ia)=A(ib,3)

B =

       1     0     0
       0     2     0
       0     4     5

Maybe there's a shorter solution, but this one works fine.

[dpb]

Very creative from the input!!! :)

[Calum]

Perfect! Thanks :)

Answer 2

[Guillaume]

The solution I had in mind when I commented on the question was:

X=[300 100 200];Y=[10 20 30];
A=[300 10 1;100 20 2;100 30 4;200 30 5];
[~, col] = ismember(A(:, 1), X);
[~, row] = ismember(A(:, 2), Y);
B=zeros(numel(Y), numel(X));
B(sub2ind(size(B), row, col)) = A(:, 3);

However, my question still stands: 'What happens when two rows of A have got the same X and Y?' The above will simply use the latest value.