PHP in a Nutshell

Chapter 6. Operators

In this chapter, we look at operators, which are the symbols such as + (adding), - (subtracting), and * (multiplying).

Operators are like functions in that they do something with values, but they use symbols rather than function names. In the equation 2 + 3, the 2 and the 3 are both operands, and the + is the operator. There are three types of operators: unary, binary, and ternary, which take one, two, and three operands respectively. As you can see, the + operator (used to add numerical values) is a binary operator, because it takes two variables as input.

Arithmetic Operators

The arithmetic operators handle basic numerical operations, such as addition and multiplication. The full list is shown in Table 6-1.

Table 6-1. The arithmetic operators

+	Addition	Returns the first value added to the second: $a + $b.
-	Subtraction	Returned the second value subtracted from the first: $a - $b.
*	Multiplication	Returns the first value multiplied by the second: $a * $b.
/	Division	Returns the first value divided by the second: $a / $b.
%	Modulus	Divides the first value into the second, then returns the remainder: $a % $b. This only works on integers, and the result will be negative if $a is negative.
+=	Shorthand addition	Adds the second value to the first: $a += $b. Equivalent to $a = $a + $b.
-=	Shorthand subtraction	Subtracts the second value from the first: $a -= $b. Equivalent to $a = $a - $b.
*=	Shorthand multiplication	Multiplies the first value ...