how to find maximum and minimum in a matrix

I have matrix A with n rows and 2 columns. I would like to find rows which has the maximum and/or minimum of X and/or Y. Then, replace zero in these rows.

For instance: I have matrix A and I would like to produce matrix B.

 A= [0.1 0.5
 0.3 0.9
 0.4 0.8
 0.4 0.2
 1 0.7
 0.2 0.6
 0.7 1
 0.2 0.9]

 Here, max. X=1    min. X=0.1     max. Y=1    min. Y=0.2

 B= [0 0
 0.3 0.9
 0.4 0.8
 0 0
 0 0
 0.2 0.6
 0 0
 0.2 0.9]

Answer 1

[Thorsten]

A= [0.1 0.5
 0.3 0.9
 0.4 0.8
 0.4 0.2
 1 0.7
 0.2 0.6
 0.7 1
 0.2 0.9]

idx = A(:,1)==max(A(:,1)) | A(:,1)==min(A(:,1)) |...
      A(:,2)==max(A(:,2)) | A(:,2)==min(A(:,2));
A(any(idx,2),:) = 0

[Maryam Hamrahi]

I really appreciate your help Thorsten. Thank you very much.

Answer 2

[Stephen23]

The simplest way would be to use logical indexing:

 >> idx = A==max(A(:)) | A==min(A(:));
 >> A(any(idx,2),:) = 0
 A =
   0.0   0.0
   0.3   0.9
   0.4   0.8
   0.0   0.0
   0.0   0.0
   0.2   0.6
   0.0   0.0
   0.2   0.9

[Maryam Hamrahi]

Many thanks Stephen Cobeldick.

I got the following error:

 Error using  == 
 Matrix dimensions must agree.

 Error in Untitled (line 9)
 idx = A==max(A) | A==min(A);

[Stephen23]

@Maryam Hamrahi: you are right, I made a mistake, and have now corrected my answer. It should work for you now.

[Maryam Hamrahi]

Thank you very much Stephen Cobeldick.

your code is working, but it gives me the wrong answer.

I want to have the following:

A =
 0.0   0.0
 0.3   0.9
 0.4   0.8
 0.0   0.0
 0.0   0.0
 0.2   0.6
 0.0   0.0
 0.2   0.9

but it gives me this:

 A =

         0         0
    0.3000    0.9000
    0.4000    0.8000
    0.4000    0.2000
         0         0
    0.2000    0.6000
         0         0
    0.2000    0.9000