What are the differences between eregi() and preg_match() in PHP, and why is eregi() deprecated?

The main differences between eregi() and preg_match() in PHP are that eregi() is case-insensitive while preg_match() is case-sensitive, and eregi() uses POSIX regular expressions while preg_match() uses Perl-compatible regular expressions. eregi() is deprecated because it is slower and less powerful than preg_match(), and using preg_match() is recommended for better performance and flexibility in regular expression matching. 

// Using preg_match() instead of eregi() to perform a case-insensitive regular expression match
$string = "Hello World";
$pattern = "/hello/i";

if (preg_match($pattern, $string)) {
    echo "Match found!";
} else {
    echo "No match found.";
}

Keywords

eregi() preg_match() differences deprecated PHP

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