Finding any row in an array and replacing with certain new values

Hi,

In an array with certain repeated (or unrepeated) row values, I'd like to replace them with new values. i.e.:

      a=[1 2 3; 4 5 6; 7 8 9; 1 2 3];
      replace [1 2 3]s with [10 11 12]s:
      new_a=[10 11 12; 4 5 6; 7 8 9; 10 11 12];
I am working with much bigger arrays and I don't know apriori how many times the row repeates itself.
So currently I am using:
a=[1 2 3; 4 5 6; 7 8 9; 1 2 3];
b=[1 2 3];
k=[10 11 12];
A=find(ismember(a,b,'rows')==1); 
[c d] = size(A);
if c > 0
for i = 1:c
a(A(i),:)=k
end
end

But I need to do this operation for dozens of times (and dozens of rows) in a loop where the new values are obtained by "ginput" which makes it very ineffective.

I would so much appreciate any better suggestions.

Many thans,

inci

Answer 1

[Thomas]

Will this help

a=[1 2 3; 4 5 6; 7 8 9; 1 2 3];
for i=1:length(a)
if a(i,:)==[1 2 3]
a(i,:)=[10 11 12]
end
end

for multiple substitutions you can add more if..else's.. Though this might not be the most elegant solution..

Answer 2

[inci]

It is much less clumsier than my solution for sure! Many thanks...