$Bill Luebkert wrote:
> Michael Louie Loria wrote:
>
>
>>I'm tesing the Text::ParseWords
>>
>>I'm new in Perl and I'm a little bit confused with the PATTERNS
>>option but I'm learning it.
>>
>>Is this code good for checking valid date in the format YYYY-MM-DD?
>>or do you have any other suggestions
>
>
> What's with the ~'s starting each line ?
>
>
>>sub isvaliddate {
>>~ my $input = shift;
>>~ if ($input =~ m!^((?:19|20)\d\d)[- /.](0[1-9]|1[012])[-
>>/.](0[1-9]|[12][0-9]|3[01])$!) {
>>~ # At this point, $1 holds the year, $2 the month and $3 the day
>>of the date entered
>>~ if ($3 == 31 and ($2 == 4 or $2 == 6 or $2 == 9 or $2 == 11)) {
>>~ return 0; # 31st of a month with 30 days
>>~ } elsif ($3 >= 30 and $2 == 2) {
>>~ return 0; # February 30th or 31st
>>~ } elsif ($2 == 2 and $3 == 29 and not ($1 % 4 == 0 and ($1 % 100
>><> 0 or $1 % 400 == 0))) {
>>~ return 0; # February 29th outside a leap year
>>~ } else {
>>~ return 1; # Valid date
>>~ }
>>~ } else {
>>~ return 0; # Not a date
>>~ }
>>}
>>
>>The link for that code is
>>http://www.regular-expressions.info/dates.html coz you might not
>>understand the code
>
>
> # test a few examples:
>
> foreach ('2005-02-30', '2005-04-31', '2005-13-30', '2005-02-35', '2005-02-00',
> '2005-01-30',) {
>
> my $bool = isvaliddate ($_); # your code
> printf "$_ is%s valid\n", $bool ? '' : ' not';
>
> $bool = is_valid_date ($_); # alternative code
> printf "$_ is%s valid\n", $bool ? '' : ' not';
> }
> exit;
>
> # Reformatted it and changed <> to != and it seems ok to me :
>
> sub isvaliddate {
> my $input = shift;
>
> # you could just use substr's and length() here instead of a RE
> # for hopefully a little more speed :
>
> # return 0 if length $input != 10 or substr ($input, 4, 1) ne '-'
> # or substr ($input, 7, 1) ne '-';
> # my $year = substr $input, 0, 4;
> # my $month = substr $input, 5, 2;
> # my $day = substr $input, 8, 2;
> # then replace $1, $2 and $3 with $year, $month and $day
>
> if ($input !~
> m#^((?:19|20)\d\d)[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$#) {
> return 0; # Not a date
> }
>
> # $1 = year, $2 = month $3 = day of month
>
> if ($3 == 31 and ($2 == 4 or $2 == 6 or $2 == 9 or $2 == 11)) {
> return 0; # 31st of a month with 30 days
> } elsif ($3 >= 30 and $2 == 2) {
> return 0; # February 30th or 31st
> } elsif ($2 == 2 and $3 == 29 and not ($1 % 4 == 0 and
> ($1 % 100 != 0 or $1 % 400 == 0))) { # <> 0 was wrong for != 0
> return 0; # February 29th outside a leap year
> }
> return 1; # Valid date
>
> }
>
> This should work as well (maybe better) - letting the system do most of the
> grunt work but is much slower than yours :
>
> sub is_valid_date {
> my $datestr = shift;
> require Time::Local;
>
> my @d = (0, 0, 12, (split /-/, $datestr)[2, 1, 0]);
> $d[4]--; $d[5] -= 1900;
> eval "Time::Local::timegm ([EMAIL PROTECTED])"; # see if it converts to
> epoch ok
> return $@ ? 0 : 1; # return 0 if error else 1
>
> }
>
> __END__
>
> Sorry for the ~ character. My MUA added it. I have tested the code and is really good but I had to change a line of code elsif ($2 == 2 and $3 == 29 and not ($1 % 4 == 0 and ($1 % 100 <> 0 or $1 % 400 == 0))) to elsif ($2 == 2 and $3 == 29 and ($1 % 4 != 0 and ($1 % 100 == 0 or $1 % 400 != 0))) coz I had errors with the former. I think the culprit was the NOT [ not ($1 % 4 == 0 and ($1 % 100 <> 0 or $1 % 400 == 0) ]. Thanks again Michael Louie Loria __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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