How to check if string has a match for the regex in PHP?

In this tutorial, you shall learn how to check if a string contains at least one match for a given regular expression in PHP using preg_match() function, with the help of example programs.

PHP – Check if string has a match for a regular expression

To check if a string contains at least one match for a given regular expression in PHP, we can use preg_match() function.

Call the preg_match() function and pass the pattern, and input string as arguments.

preg_match($pattern, $str)

If the string $str contains a match for the regular expression $pattern, then the function returns 1. If there is no match, then the function returns 0. Or else in case of any error, a boolean value of false is returned.

Examples

1. Check if string has a match for “fox”, case insensitive

In this example, we take a test string $str, and check if the string contains the "fox" and the matching has to happen insensitive to case. The pattern would be "/fox/i".

PHP Program

<?php
$str = "The quick brown fox jumps over the lazy dog.";
$pattern = "/fox/i";
if(preg_match($pattern, $str)) {
  echo "There is a match.";
} else {
  echo "There is no match.";
}
?>

Output

Now, let us take another test string and check if it has a match for the "fox".

PHP Program

<?php
$str = "The cat in the hat sat on the mat.";
$pattern = "/fox/i";
if(preg_match($pattern, $str)) {
  echo "There is a match.";
} else {
  echo "There is no match.";
}
?>

Output

Reference to tutorials related to program

• PHP If Else
• PHP echo

Conclusion

In this PHP Tutorial, we learned how to check if the string has a match for a given pattern, or not, using preg_match() function, with the help of examples.