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How do we assure that the date is in the correct format and is actually a valid date? In this video, we'll explore one option for validating string formats and checking for a valid date.
Documentation
explode() Split a string by string
strlen() Get string length
checkdate() Validate a Gregorian date
Regular Expressions
Another option you often see for validating strings, is the use of regular expressions. A regular expression (regex or regexp for short) is a special text string for describing a search pattern. Regular expressions are a great tool to learn. Most applications as well as most programming languages include some form of regular expression matching.
PHP includes a number of Regular Expression Functions. We could use preg_match to match our dates as well.
Example:
if (preg_match('/^(\d{2})\/(\d{2})\/(\d{4})$/', $date, $dateMatch)) {
if (!checkdate($dateMatch[1], $dateMatch[2], $dateMatch[3])) {
$error_message = 'Invalid Date';
}
} else {
$error_message = 'Invalid Date format';
}
This matches a string that starts with (^) 2 digits (\d{2}), followed by a forward slash (\/), then another 2 digits (\d{2}) followed by another forward slash (\/), and finally 4 digits (\d{4}) at the end($).
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