PHP quick reference

Everyday functions on one page.

Function	Purpose
`strlen / strtolower`	Length / change case
`str_contains($s, $x)`	Search a string
`explode / implode`	Split a string / join an array
`count($a)`	Array length
`in_array($x, $a)`	Is it in the array?
`array_map / array_filter`	Transform / keep some items
`json_encode / json_decode`	To and from JSON
`htmlspecialchars($s)`	Make text safe to print
`password_hash / password_verify`	Handle passwords
`$_GET / $_POST / $_SESSION`	Request and session data