Multiplication

The * operator in PHP is a binary arithmetic operator used for multiplication. It calculates and returns the mathematical product of two numeric operands.

$result = $expression1 * $expression2;

Precedence and Associativity

• Precedence: The * operator has higher precedence than addition (+) and subtraction (-), but shares the same precedence level as division (/) and modulo (%).
• Associativity: It is left-associative. In an expression containing multiple operators of the same precedence level, evaluation proceeds strictly from left to right.

Type Resolution and Coercion

The behavior and return type of the * operator depend strictly on the data types of the evaluated operands and the platform’s integer limits:

• Integer Evaluation: If both operands are of type int, the operator returns an int, provided the resulting product does not exceed the platform’s maximum integer threshold (PHP_INT_MAX) and does not fall below the platform’s minimum integer threshold (PHP_INT_MIN).
• Float Evaluation: If at least one operand is of type float, the operator returns a float.
• Integer Overflow and Underflow: If the product of two int operands exceeds PHP_INT_MAX (positive overflow) or falls below PHP_INT_MIN (negative overflow), PHP automatically promotes the return type to a float to accommodate the magnitude of the value.
• Implicit Coercion: If an operand is a numeric string (e.g., "5" or "3.14"), PHP implicitly casts the string to the corresponding int or float type before performing the multiplication.
• Strict Typing Exceptions: In PHP 8.0 and later, attempting to use the * operator on non-numeric strings or incompatible types (like arrays or objects without numeric casting capabilities) throws a TypeError.

Syntax Visualization

// Standard integer multiplication (Returns int)
$val1 = 4 * 3;           // int(12)

// Float multiplication (Returns float)
$val2 = 4.5 * 2;         // float(9.0)

// Mixed type multiplication (Returns float)
$val3 = 5 * 1.2;         // float(6.0)

// Implicit type coercion from numeric string (Returns int)
$val4 = "10" * 5;        // int(50)

// Integer overflow promotion (Returns float)
$val5 = PHP_INT_MAX * 2; // float(...)

// Integer underflow promotion (Returns float)
$val6 = PHP_INT_MIN * 2; // float(...)

// Precedence and left-associativity
$val7 = 2 + 3 * 4;       // int(14)  (Multiplication evaluates before addition)
$val8 = 10 / 2 * 5;      // int(25)  (Evaluates left-to-right: (10 / 2) * 5)

Master PHP with Deep Grasping Methodology!

Learn More