How can I make a random array with values of either -1 or 1?

I'm trying to use randi to make a matrix filled with either -1 or 1 however randi also includes 0s.

Answer 1

[Image Analyst]

Try this:

r = 2 * randi(2) - 3

I just answered this very recently.

[Quinlin Hamill]

Thank you, this is great

Answer 2

[George]

You can use rand

% pseudo code

x = rand(50,1);
pos = x >= .5;
neg = x < .5;
x(pos) = 1;
x(neg) = -1;

This suffers from the fact that you have to make a decision when randn returns 0.5 exactly..