Scaling a certain element

Hello

How do I scale a certain element in a matrix

if I want to get a certain type of element, like just the 2's or 5's and multiply them

A = [ 1 2 2; 4 5 1]

A==5 or A==2 MULTIPLY by 3

etc

thanks

Answer 1

[madhan ravi]

n=5; % certain element
idx=ismember(A,n);
a=A(:);
a(idx)=a(idx)*3;
R=reshape(a,size(A))

%OR
n=5;
idx=find(ismember(A,n));
[I,J]=ind2sub(size(A),idx);
R=A;
R(I,J)=R(I,J)*3