PHP Skills Tests

Operator precedence

PHP's operator precedence.

Associativity	Operators	Additional information
non-associative	clone new	clone and new
left	[	array()
right	**	arithmetic
right	++ -- ~ (int) (float) (string) (array) (object) (bool) @	types and increment/decrement
non-associative	instanceof	types
right	!	logical
left	* / %	arithmetic
left	+ - .	arithmetic and stirng
left	<< >>	bitwise
non-associative	< <= >= >	comparison
non-associative	== != === !== <> <=>	comparison
left	&	bitwise and references
left	^	bitwise
left	`|	bitwise
left	&&	http://php.net/manual/en/language.operators.logical.php logical]
left	||	logical
right	??	comparison
left	? :	ternary
right	= += -= *= /= .= %= &= |= ^= <<= >>= =>	assignment
left	and	logical
left	xor	logical
left	or	logical
left	,`	many uses

Associativity

TK

Hexidecimal values

echo 0x500;
1280

This is hexidecimal notation. The value is calculated 0 * 1 = 0 + 0 * 16 = 0 + 5 * 256 = 1280.

Bit shifting

TK

is_numeric()

• Valid values: "200", ".25e4", "20,2"
• Invalid values: "$200"

Magical constants

Magical constants are constants that change value depending on where in the code they are placed.

The magical constants in PHP are

• __LINE__
• __FILE__
• __DIR__
• __FUNCTION__
• __CLASS__
• __TRAIT__
• __METHOD__
• __NAMESPACE__