Date regular expression

PureDrive

Hi guys, I wrote this regular expression for date validation. Does it look alright to you? Thanks

$date_pattern = ⁽ ([01][1-9]) | [1-9] ) [-/] ( [0123][0-9] ) [-/] ( [1-9][0-9]{3} );

NogDog

Assuming we're using PCRE regular expressions, I'd probably use:

$date_pattern = '#^(0?[1-9]|1[012])[-/](0?[1-9]|[12]\d|3[01])[-/][1-9]\d{3}$#';
if(preg_match($date_pattern, $date)
{
   // valid
}
else
{
   // invalid
}

However, this still does not guarantee that a given date is valid (since 02/30/2007 or 11/31/2008 would validate OK but are not actually valid). Depending on the source of the data, you may want to separate it into month, day, and year values and run them through [man]checkdate/man.

PureDrive

Thanks NogDog. What's the purpose of the '#' signs in regular expressions?

NogDog

PCRE patterns must begin and end with a delimiter character. Traditionally, the "/" is used, but other characters are also allowed. I opted to use "#" since the regular expression is using "/" characters, and by doing so I do not have to escape those "/" characters with a "\". (The main purpose of the delimiter is that a number of modifiers may follow the ending delimiter. (See PCRE pattern syntax for more info.)

PureDrive

I changed my reg ex a little to this:

$date_pattern = "^( (0?[1-9]) | 1[012] ) [-/] ( [0123][0-9] ) [-/] ( [1-9][0-9]{3} )";

And from some reason it doesn't work when I do ereg( $date_pattern, $date ). My regular expression seems to be correct though. Can you spot a problem with it? thanks

NogDog

For one thing, all those spaces within the pattern will be treated as literal spaces; so you will need to close up all the extraneous spaces between parentheses and such.

PS: Note that the ereg() functions are considered to be more or less deprecated in favor of the preg() (PCRE) functions, thus the reason I was concentrating on the latter in my previous replies.