PHP Interview Questions – Operators

1. (Asked in Infosys) What are operators in PHP? Mention their types.

Answer:
Operators are symbols used to perform operations on variables and values. PHP supports several operator types:

• Arithmetic operators
• Assignment operators
• Comparison operators
• Logical operators
• Increment/Decrement operators
• String operators
• Array operators

2. (Asked in TCS) Explain arithmetic operators with an example.

Answer:
Arithmetic operators are used to perform mathematical operations.

Example:

$a = 10;
$b = 5;

echo $a + $b; // 15 (Addition)
echo $a - $b; // 5  (Subtraction)
echo $a * $b; // 50 (Multiplication)
echo $a / $b; // 2  (Division)
echo $a % $b; // 0  (Modulus - remainder)

3. (Asked in Cognizant) What is the difference between the ‘==’ and ‘===’ operators in PHP?

Answer:

• == (Equal) checks if two values are equal, ignoring data type.
• === (Identical) checks if two values are equal, considering both value and data type.

Example:

$a = "5";
$b = 5;

var_dump($a == $b);  // true
var_dump($a === $b); // false

4. (Asked in Google) How does the assignment operator (=) work in PHP?

Answer:
The assignment operator assigns a value to a variable.

Example:

$name = "Rahul"; // Assigns "Rahul" to $name

5. (Asked in Accenture) Explain increment and decrement operators with examples.

Answer:
These operators increase or decrease a variable’s value by 1.

Example:

$x = 5;
echo ++$x; // Output: 6 (pre-increment)

$y = 5;
echo $y++; // Output: 5, then $y becomes 6 (post-increment)

6. (Asked in Amazon) What are logical operators in PHP? Give an example.

Answer:
Logical operators combine conditional statements (&&, ||, !).

Example:

$a = true;
$b = false;

if ($a && !$b) {
  echo "Condition met"; // This line executes
}

7. (Asked in IBM) What is a string operator in PHP?

Answer:
The string operator (.) concatenates (joins) two or more strings.

Example:

$first_name = "Amit";
$last_name = "Sharma";

echo $first_name . " " . $last_name; // Output: Amit Sharma

8. (Asked in Capgemini) Explain array operators in PHP with an example.

Answer:
Array operators are used to combine or compare arrays.

Example:

$arr1 = ["a" => 1, "b" => 2];
$arr2 = ["c" => 3, "d" => 4];

$combined = $arr1 + $arr2; // Union of arrays
print_r($combined);
// Output: Array ( [a] => 1 [b] => 2 [c] => 3 [d] => 4 )

9. (Asked in Facebook) What is the use of the spaceship operator (<=>) in PHP?

Answer:
The spaceship operator (<=>) compares two values and returns:

• 0 if both values are equal.
• 1 if the left side is greater.
• -1 if the right side is greater.

Example:

echo 5 <=> 5; // Output: 0
echo 7 <=> 5; // Output: 1
echo 3 <=> 5; // Output: -1

10. (Asked in Microsoft) What is operator precedence in PHP? Why is it important?

Answer:
Operator precedence determines the order in which PHP evaluates expressions. Understanding precedence ensures correct and expected results.

Example:

echo 2 + 3 * 4; // Output: 14, multiplication happens first (3*4=12, then +2)
echo (2 + 3) * 4; // Output: 20, parentheses first (2+3=5, then *4)