Function to check if a string is a date
PhpRegexValidationDateDatetimePhp Problem Overview
I am trying to write a function to determine if a string is a date/time using PHP. Basically a valid date/time would look like:
2012-06-14 01:46:28
Obviously though its completely dynamic any of the values can change, but it should always be in form of XXXX-XX-XX XX:XX:XX, how can I write a regular expression to check for this pattern and return true if matched.
Php Solutions
Solution 1 - Php
If that's your whole string, then just try parsing it:
if (DateTime::createFromFormat('Y-m-d H:i:s', $myString) !== false) {
// it's a date
}
Solution 2 - Php
Easiest way to check if a string is a date:
if(strtotime($date_string)){
// it's in date format
}
Solution 3 - Php
Here's a different approach without using a regex:
function check_your_datetime($x) {
return (date('Y-m-d H:i:s', strtotime($x)) == $x);
}
Solution 4 - Php
In case you don't know the date format:
/**
* Check if the value is a valid date
*
* @param mixed $value
*
* @return boolean
*/
function isDate($value)
{
if (!$value) {
return false;
}
try {
new \DateTime($value);
return true;
} catch (\Exception $e) {
return false;
}
}
var_dump(isDate('2017-01-06')); // true
var_dump(isDate('2017-13-06')); // false
var_dump(isDate('2017-02-06T04:20:33')); // true
var_dump(isDate('2017/02/06')); // true
var_dump(isDate('3.6. 2017')); // true
var_dump(isDate(null)); // false
var_dump(isDate(true)); // false
var_dump(isDate(false)); // false
var_dump(isDate('')); // false
var_dump(isDate(45)); // false
Solution 5 - Php
In my project this seems to work:
function isDate($value) {
if (!$value) {
return false;
} else {
$date = date_parse($value);
if($date['error_count'] == 0 && $date['warning_count'] == 0){
return checkdate($date['month'], $date['day'], $date['year']);
} else {
return false;
}
}
}
Solution 6 - Php
I use this function as a parameter to the PHP filter_var function.
- It checks for dates in
yyyy-mm-dd hh:mm:ssformat - It rejects dates that match the pattern but still invalid (e.g. Apr 31)
function filter_mydate($s) {
if (preg_match('@^(\d\d\d\d)-(\d\d)-(\d\d) (\d\d):(\d\d):(\d\d)$@', $s, $m) == false) {
return false;
}
if (checkdate($m[2], $m[3], $m[1]) == false || $m[4] >= 24 || $m[5] >= 60 || $m[6] >= 60) {
return false;
}
return $s;
}
Solution 7 - Php
Although this has an accepted answer, it is not going to effectively work in all cases. For example, I test date validation on a form field I have using the date "10/38/2013", and I got a valid DateObject returned, but the date was what PHP call "overflowed", so that "10/38/2013" becomes "11/07/2013". Makes sense, but should we just accept the reformed date, or force users to input the correct date? For those of us who are form validation nazis, We can use this dirty fix: https://stackoverflow.com/a/10120725/486863 and just return false when the object throws this warning.
The other workaround would be to match the string date to the formatted one, and compare the two for equal value. This seems just as messy. Oh well. Such is the nature of PHP dev.
Solution 8 - Php
if (strtotime($date) > strtotime(0)) {
echo 'it is a date'
}
Solution 9 - Php
I found my answer here https://stackoverflow.com/a/19271434/1363220, bassically
$d = DateTime::createFromFormat($format, $date);
// The Y ( 4 digits year ) returns TRUE for any integer with any number of digits so changing the comparison from == to === fixes the issue.
if($d && $d->format($format) === $date) {
//it's a proper date!
}
else {
//it's not a proper date
}
Solution 10 - Php
I wouldn't use a Regex for this, but rather just split the string and check that the date is valid:
list($year, $month, $day, $hour, $minute, $second) = preg_split('%( |-|:)%', $mydatestring);
if(!checkdate($month, $day, $year)) {
/* print error */
}
/* check $hour, $minute and $second etc */
Solution 11 - Php
If your heart is set on using regEx then txt2re.com is always a good resource:
<?php
$txt='2012-06-14 01:46:28';
$re1='((?:2|1)\\d{3}(?:-|\\/)(?:(?:0[1-9])|(?:1[0-2]))(?:-|\\/)(?:(?:0[1-9])|(?:[1-2][0-9])|(?:3[0-1]))(?:T|\\s)(?:(?:[0-1][0-9])|(?:2[0-3])):(?:[0-5][0-9]):(?:[0-5][0-9]))'; # Time Stamp 1
if ($c=preg_match_all ("/".$re1."/is", $txt, $matches))
{
$timestamp1=$matches[1][0];
print "($timestamp1) \n";
}
?>
Solution 12 - Php
function validateDate($date, $format = 'Y-m-d H:i:s')
{
$d = DateTime::createFromFormat($format, $date);
return $d && $d->format($format) == $date;
}
Solution 13 - Php
If you have PHP 5.2 Joey's answer won't work. You need to extend PHP's DateTime class:
class ExDateTime extends DateTime{
public static function createFromFormat($frmt,$time,$timezone=null){
$v = explode('.', phpversion());
if(!$timezone) $timezone = new DateTimeZone(date_default_timezone_get());
if(((int)$v[0]>=5&&(int)$v[1]>=2&&(int)$v[2]>17)){
return parent::createFromFormat($frmt,$time,$timezone);
}
return new DateTime(date($frmt, strtotime($time)), $timezone);
}
}
and than you can use this class without problems:
ExDateTime::createFromFormat('d.m.Y G:i',$timevar);
Solution 14 - Php
This solves for me, but also presents various other problems I think.
function validateTimeString($datetime, $format = "Y-m-d H:i:s"){
return ($datetime == date($format, strtotime($datetime)));
}
Solution 15 - Php
When I work with unconventional APIs, I sometimes get a bit of a messy return instead of a well defined date format. So I use a rather inelegant class and I readily admit that it is brutal and unconventional in principle but it does me good sometimes ^^.
class DateHelper
{
private const DATE_FORMATS = [
DATE_ATOM,
DATE_COOKIE,
DATE_RFC822,
DATE_RFC850,
DATE_RSS,
DATE_W3C,
"Y-m-d\TH:i:s.u",
'Y-m-d\TH:i:s',
"Y-m-d'T'H:i:s.SSS'Z'",
"Y-m-d\TH:i:s.uP",
"Y-m-d\TH:i:sP",
"d/m/Y H:i:s",
];
/**
* @param string $inputStringDate
* @return DateTime|null
*/
public static function createDateFromUnknownFormat(string $inputStringDate): ?DateTime
{
$inputStringDate = str_replace('/', '-', $inputStringDate);
preg_match('/^(\d{4})\-(\d{2})-(\d{2})$/', $inputStringDate, $result);
if (!empty($result)) {
return DateTime::createFromFormat('Y-m-d', $inputStringDate);
}
preg_match('/^(\d{2})\-(\d{2})-(\d{4})$/', $inputStringDate, $result);
if (!empty($result)) {
return DateTime::createFromFormat('d-m-Y', $inputStringDate);
}
foreach (self::DATE_FORMATS as $dateFormat) {
if ($dateObject = DateTime::createFromFormat($dateFormat, $inputStringDate)) {
return $dateObject;
}
}
return null;
}
}
Solution 16 - Php
A simple solution is:
echo is_numeric( strtotime( $string ) ) ? 'Yes' : 'No';
Solution 17 - Php
strtotime? Lists? Regular expressions?
What's wrong with PHP's native DateTime object?