What are the potential pitfalls of using the plus sign (+) for string concatenation in PHP?

Using the plus sign (+) for string concatenation in PHP can lead to unexpected results, as it is primarily used for arithmetic operations. To avoid this pitfall, it is recommended to use the concatenation operator (.) instead. This ensures that strings are concatenated correctly without any unintended conversions or errors.

// Incorrect way using the plus sign
$string1 = "Hello";
$string2 = "World";
$result = $string1 + $string2; // This will result in 0 instead of "HelloWorld"

// Correct way using the concatenation operator
$string1 = "Hello";
$string2 = "World";
$result = $string1 . $string2; // This will result in "HelloWorld"