How to code a generic for loop that removes a row with missing requirement

I am trying to create a generic program using a for loop that removes the row if a user checks their number against it and it is not there. A matrix will have unspecified number of rows and columns, a user will input their value say n, if the user's n is not in row k of A, row k should be deleted.

A = magic(50);
row = size(A,1);
n = 3; %or whatever number
for r = 1:1:row
    if not(ismember(n, A)) %if n is not a member of whatever row it is on, it should be deleted
        %what goes in here?
    end
end

Answer 1

[Voss]

A = magic(50);
row = size(A,1);
n = 3; %or whatever number
rows_to_delete = [];
for r = 1:1:row
  if ~ismember(n, A(r,:)) %if n is not a member of whatever row it is on, it should be deleted
      rows_to_delete(end+1) = r;
  end
end
% delete the rows
A(rows_to_delete,:) = [];

[Voss]

Or, without the loop:

A = magic(50);
n = 3;
A(~any(A == n,2),:) = [];

[Andromeda]

This is exactly what I was looking for, thank you!

[Voss]

You're welcome!