Reading some php code, you might get confused about the difference betweeen =, ==, and === (this single, double, and triple equal signs). Here's a quick summary.
= (Assignment) Just like in (pretty much) every other programming language.
== (Equality) Returns true if the two variables have the same value.
=== (Identity) Returns true if the two variables have the same value AND the same type (integer 0 is not equal to, in the === sense, float 0 or string 0).
Hope that clears up confusion. It did for me.