PHP Operator Precedence

The precedence of an operator is important to bind two expressions together. For example, in the expression 1 + 5 * 3, the answer is 16 and not 18 because the "*" operator has a higher precedence than the "+" operator.
Parentheses may be used to force precedence, if necessary. For instance: (1 + 5) * 3 evaluates to 18. If operator precedence is equal, left to right associativity is used.
The following table lists the precedence of operators with the highest-precedence operators listed at the top of the table.

Associativity	Operators	Additional Information
non-associative	clone new	clone and new
left	[	array()
non-associative	++ --	increment/decrement
non-associative	~ - (int) (float) (string) (array) (object) (bool) @	types
non-associative	instanceof	types
right	!	Logical
left	* / %	arithmetic
left	+ - .	arithmetic and string
left	<< >>	bitwise
non-associative	< <= > >= <>	comparison
non-associative	== != === !==	comparison
left	&	bitwise and references
left		bitwise
left	|	bitwise
left	&&	logical
left	||	logical
left	? :	ternary
right	= += -= *= /= .= %= &= |= = <<= >>=	assignment
left	and	logical
left	xor	logical
left	or	logical
left	,	many uses

Left associativity means that the expression is evaluated from left to right, right associativity means from right to left.