What are the advantages of using strpos() over regular expressions for simple string checks in PHP?

When performing simple string checks in PHP, using strpos() is generally more efficient than using regular expressions. This is because strpos() is a built-in function specifically designed for finding the position of a substring within a string, whereas regular expressions are more complex and can be slower for simple tasks. Additionally, strpos() is easier to read and understand for basic string manipulation tasks.

// Using strpos() to check if a substring exists in a string
$string = "Hello, world!";
$substring = "world";
if (strpos($string, $substring) !== false) {
    echo "Substring found!";
} else {
    echo "Substring not found!";
}