What is the easiest way to remove a vector from a matrix?

Suppose there is a Loop A which returns a row vector y of the same number of columns such as matrix Q.

I want to remove all the occurrences of the row vectors y from Q, is their a simple way to do it (I am trying to avoid loops).

Here is a loop I wrote:

for i=1:size(Q,1)
s=eq(Q(i,:),y); r=all(s);
if r==1
Q(i,:)=[];
end
end

Answer 1

[Chunru]

a = magic(4);
a = [a; a(1, :); a];        % 1st 5th and 6th rows are the same
a

a = 9×4

16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1 16 2 3 13 16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1

y = a(1, :);                % the vector input
idx = all(a == y, 2);
a(idx, :)=[]

a = 6×4

5 11 10 8 9 7 6 12 4 14 15 1 5 11 10 8 9 7 6 12 4 14 15 1

% in a line
% a(all(a==y, 2), :) =[]

[TADA]

Nice :)

[Cantor Set]

y = a(1, :);  Y=rep(y,[size(a,1),1]) ;              % replicating y 
idx = all(a == Y, 2);
a(idx, :)=[]

We need to replicate y so that we use a==Y :)

What does this line mean a(idx, :)=[] ?

[TADA]

this removes the lines that correspond to the indices in idx

I suggest you read the documentation on indexing

[Chunru]

@Chad Greene You don't have to replicate y (matlab does auto array expansion).

Answer 2

[TADA]

A = [magic(5); magic(5)];
v = A(1,:);
mask = A==v;
eqRows = all(mask, 2);
A(eqRows, :) = [];