PHP Functions of Contention

Information on PHPs isset(), empty() and is_null() functions; and the differences in responses.

Value of Variable	`isset()`	`empty()`	`is_null()`
"" (an empty string)	bool(true)	bool(true)
" " (space)	bool(true)
FALSE	bool(true)	bool(true)
TRUE	bool(true)
array() (an empty array)	bool(true)	bool(true)
NULL		bool(true)	bool(true)
"0" (0 as a string)	bool(true)	bool(true)
0 (0 as an integer)	bool(true)	bool(true)
0.0 (0 as a float)	bool(true)	bool(true)
var ; (a variable declared, but without a value)		bool(true)	bool(true)
NULL byte ("")	bool(true)

This page has been created as I kept losing where I found this on the internet. It covers certain PHP functions that have interesting functionality.