How can PHP be optimized to efficiently handle input validation for alphanumeric characters only?

To efficiently handle input validation for alphanumeric characters only in PHP, you can use regular expressions to check if the input contains only alphanumeric characters. This can be done by using the preg_match function with the appropriate regular expression pattern to match only alphanumeric characters. 

$input = "abc123"; // Input to validate

if (preg_match('/^[a-zA-Z0-9]*$/', $input)) {
    echo "Input contains only alphanumeric characters.";
} else {
    echo "Input contains non-alphanumeric characters.";
}

Keywords

PHP input validation alphanumeric characters optimization efficiency

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