List of PHP operator types 
OPERATOR TYPE OPERANDS (SYMBOLS) DESCRIPTION
the array type UNION (+), EQUAL (==), IDENTICAL (===), NOT EQUAL (!=), NOT EQUAL (<>), NOT IDENTICAL (!==) The array operators are used compare two or more arrays (similar to comparison type)
the arithmetic type ADDITION (+), SUBTRACTION (-), MULTIPLICATION (*), DIVISION, (/), MODULUS (%), EXPONENTIATION (**) The arithmetic operators are used for basic mathematical operations.
the assignment type EQUALS TO (=), MULTIPLY / ASSIGN (*=), DIVIDE / ASSIGN (/=), MODULUS / ASSIGN (%=), ADD / ASSIGN (+=), SUBTRACT / ASSIGN (-=), REFERENCE TO (&$) The assignment operators are used to assign values to variables and, in combination with other operator types, as shorthand for compound assignments.).
the bitwise type NOT (~), AND (&), OR (|), XOR (^), LEFT-SHIFT (<<), SIGNED RIGHT SHIFT (>>), UNSIGNED RIGHT SHIFT (>>>) The bitwise operators work with numbers on their basic binary levels.
the comparison type EQUAL (==), IDENTICAL (===), NOT EQUAL (!=), NOT EQUAL (<>), NOT IDENTICAL (!==), LESS THAN (<), GREATER THAN (>), LESS THAN / EQUAL (<=), GREATER THAN / EQUAL (>=) The comparison operators are used to do compare two values together and choose the further code flow.
the error control type ERROR AT (@) The error control operator is used to detect erros in code and direct flow accordingly.
the execution type EXECUTION (``) The execution operator is used to execute shell commands.
the increment / decrement type INCREMENT (++), DECREMENT (--) The increment and decrement operators are used to increment / decrement a variable's value.
the logical type NOT (!), AND (&&), AND (and), OR (||), OR (or), XOR (xor) The logical operators are used to evaluate Boolean results of a logical comparison.
the string type CONCATENATE (.), APPEND (.=) The string operators are used to assist string manipulation.
the type type TYPE (instanceof) The type operator is used to determine if a variable is an object or a class.