What are some common pitfalls to watch out for when comparing values in PHP?

One common pitfall when comparing values in PHP is using the == operator instead of the === operator. The == operator only checks for equality in terms of value, while the === operator also checks for equality in terms of data type. This can lead to unexpected results when comparing variables of different types. To avoid this pitfall, always use the === operator for strict comparisons.

// Incorrect comparison using the == operator
$value1 = 5;
$value2 = '5';

if ($value1 == $value2) {
    echo 'Values are equal.';
} else {
    echo 'Values are not equal.';
}

// Correct comparison using the === operator
if ($value1 === $value2) {
    echo 'Values are equal.';
} else {
    echo 'Values are not equal.';
}