Question

I want to run a function that has 2 different outcomes, but I want each outcome to be truly 50%. I am assuming rand(0,1) is the way to go, but I am curious if that could possibly favor one over the other. What is the best way to get a 50/50 outcome?

Thanks.

EDIT: thanks guys I don’t want it to be random though, I want the outcome to be 101010101 not 111001101. Maybe I should just update a data-base with the last value output and then return the opposite?

EDIT2: OK I am sorry my last edit was misleading. I am only calling the function once per user and assigning that value as a cookie to the user. I want each visiting user to receive a 1 or a 0 in the order 1010101.

Answer 1

Depending on the specific context in which you will use this number (e.g. a per-user basis, lifetime of application, etc.) you can store it in a number of locations, $_SESSION, a database value, or if the scope only covers the current page then you can save it on directly in that page’s code.

An easy way to toggle the value is:

$val = 1 - $val; 

For a database call:

UPDATE YourTable SET `next_value` = 1 - `next_value` 

etc…