How can I create the following vector??

I have a vector called "y", which is for plotting values in the y axis. Also, I have a variable which is a scalar number, but I want to create a vector with the number of places of "y", but having all values of this vector the same value of that variable.

As an example: y = 0:0.5:3;

r = 30

r' = [30 30 30 30 30 30]

The thing is that my vector "y" is much longer than that.

So, how can I create the vector called "r'"?

Answer 1

[Adam]

r = repmat( 30, [numel(y), 1] );

or

r = 30 * ones( numel(y), 1 );

or

r = 30 + zeros( numel(y), 1 ) );

I haven't tested which is more efficient.

[Guillaume]

or

r = repelem(30, numel(y));

in R2015a or later