NUX = new user experience
- Constructor Argument Promotion —- The class members will automatically be created and assigned to what is passed into the constructor.
- lambad function using ==> e.g., $squared = array_map($x ==> $x*$x, array(1,2,3));
make a choice from a range of possibilities.
=== compare value and type
== compare only value
<=> compare which is larger (only gives value -1, 0, 1)