Numbers only regex (digits only) PHP
Numbers only (or digits only) regular expressions can be used to validate if a string contains only numbers.
Basic numbers only regex
Below is a simple regular expression that allows validating if a given string contains only numbers:
"/^\\d+$/"
Enter a text in the input above to see the result
Example code in PHP:
// Validate if a string is a valid number
$number_validation_regex = "/^\\d+$/";
echo preg_match($number_validation_regex, '42'); // returns 1
// Extract number from a string
$extract_number_pattern = "/\\d+/";
$string_to_match = 'Your message was viewed 203 times.';
preg_match_all($extract_number_pattern, $string_to_match, $matches);
print_r($matches[0])// matches[0] is ['203']
Real number regex
Real number regex can be used to validate or exact real numbers from a string.
"/^(?:-(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))|(?:0|(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))))(?:.\\d+|)$/"
Enter a text in the input above to see the result
Example code in PHP:
// Validate if a string is a valid real number
$number_validation_regex = "/^(?:-(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))|(?:0|(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))))(?:.\\d+|)$/";
echo preg_match($number_validation_regex, '121220.22'); // returns 1
// Extract real number from a string
$extract_number_pattern = "/(?:-(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))|(?:0|(?:[1-9](?:\\d{0,2}(?:,\\d{3})+|\\d*))))(?:.\\d+|)/";
$string_to_match = 'Pi equals to 3.14';
preg_match_all($extract_number_pattern, $string_to_match, $matches);
print_r($matches[0])// matches[0] is ['3.14']
Notes on number only regex validation
In PHP you can also validate number by using is_numeric function:
is_numeric("123") // returns TRUE
