PHP Operators

PHP Operators

Operators perform operations on variables and values.

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Comparison Operators

Compare two values and return a boolean result.

Operator	Name	Example	Result
==	Equal	5 == "5"	true (type coercion)
===	Identical	5 === "5"	false (strict)
!=	Not equal	5 != 3	true
!==	Not identical	5 !== "5"	true (strict)
>	Greater than	10 > 5	true
<	Less than	3 < 7	true
>=	Greater or equal	5 >= 5	true
<=	Less or equal	4 <= 3	false

Loose vs Strict Comparison

$a = 10;
$b = "10";

$a == $b   // true (values equal, types ignored)
$a === $b  // false (different types)

// Common type coercion cases
0 == false      // true
0 === false     // false
"0" == 0        // true
"0" === 0       // false

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Logical Operators

Combine multiple conditions.

Operator	Name	Description
&& or and	AND	Both conditions must be true
|| or or	OR	At least one must be true
!	NOT	Reverses the condition
xor	XOR	Exactly one must be true

// AND - both must be true
if ($age >= 21 && $income >= 30000) {
    echo "Approved";
}

// OR - at least one must be true
if ($age >= 65 || $income < 20000) {
    echo "Eligible for discount";
}

// NOT - reverses boolean
if (!$isLoggedIn) {
    echo "Please login";
}

// XOR - exactly one must be true
if ($useCreditCard xor $usePayPal) {
    echo "Payment method selected";
}

Operator precedence: ! → && → ||. Use parentheses for clarity.

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Arithmetic Operators

Operator	Name	Example	Result
+	Addition	5 + 3	8
-	Subtraction	10 - 4	6
*	Multiplication	4 * 3	12
/	Division	15 / 3	5
%	Modulus	10 % 3	1
**	Exponentiation	2 ** 3	8

$total = $price * $quantity - $discount;
$isEven = ($number % 2 == 0);

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Assignment Operators

Operator	Example	Equivalent
=	$a = 5	Assign
+=	$a += 3	$a = $a + 3
-=	$a -= 2	$a = $a - 2
*=	$a *= 4	$a = $a * 4
/=	$a /= 2	$a = $a / 2
.=	$a .= "x"	$a = $a . "x"

$total = 0;
$total += 50;      // 50
$message = "Hi";
$message .= "!";   // "Hi!"

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Increment/Decrement

Operator	Description
++$a	Pre-increment (increment, then return)
$a++	Post-increment (return, then increment)
--$a	Pre-decrement
$a--	Post-decrement

$count = 5;
echo $count++;  // 5, then becomes 6
echo ++$count;  // 7, then outputs 7

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String Operators

Operator	Name	Example
.	Concatenation	"Hi" . " there"
.=	Append	$a .= " more"

$name = $firstName . " " . $lastName;
$html = "<div>";
$html .= "<p>Content</p>";
$html .= "</div>";

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Things to Notes

1. Use strict comparison (===) unless you need type coercion.
2. Use parentheses when combining multiple logical operators for clarity.
3. Use compound operators (+=, -=, .=) for cleaner code.
4. Be aware of type coercion with == vs ===.