regex match cond1 OR match cond2 in single command - php

Question

I need to check if entered date is between 2019-09-01 - 2019-12-31
I can do this as follows: $koodi is user input
$pattern1 = "/^2019-(09|11)-([0-2][0-9]|30)$/";
$pattern2 = "/^2019-(10|12)-([0-2][0-9]|3[0-1])$/";
if(preg_match($pattern1, $koodi) || preg_match($pattern2, $koodi)) {
echo "<code>$koodi</code> ok!<br>\n";
}
else {
echo ("<code>$koodi</code> NOT ok!<br>\n");
}
I was trying to make those two conditions into single regex statement, is that possible and if so how?
I tried:
$pattern = "/^2019-(09|11)-([0-2][0-9]|30)$ | ^2019-(10|12)-([0-2][0-9]|3[0-1])$/";
Did not work, neither the following where i tried to put parentheses around conditions:
$pattern = "/(^2019-(09|11)-([0-2][0-9]|30)$) | (^2019-(10|12)-([0-2][0-9]|3[0-1])$)/";

Answer 1

Please don't use a regex to do that, what if the dates change or what if the next developer has to come and work on this and figure out what your doing?
According to this article you can check if a date is between 2 dates by doing something like this.
<?php
$currentDate = date('Y-m-d');
$currentDate = date('Y-m-d', strtotime($currentDate));
$startDate = date('Y-m-d', strtotime("01/09/2019"));
$endDate = date('Y-m-d', strtotime("01/10/2019"));
if (($currentDate >= $startDate) && ($currentDate <= $endDate)){
echo "Current date is between two dates";
}else{
echo "Current date is not between two dates";
}
as for why your patterns didn't work its because you have a space around the pipe in the middle and you may possibly need to wrap the whole thing in brackets. You also have the $ half way through the regex which is matching the whole string, I would usually only have it at the end, like this: -
^(regex1|regex2)$
I haven't written the correct version in case your tempted to use it, (please use the date objects method)