A regexp, a lookup table and (core module) Time::Local.

use Time::Local qw( timelocal );

my %month_num_by_name = (
   JAN => 1,
   FEB => 2,
   ...
);

my ($d, $m, $y) = split(/-/, $date);
$m = $month_num_by_name{$m};

my $time = timelocal(0, 0, 0, $d, $m-1, $y);
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Update: Added code.

I think timelocal() wants the year to be years since 1900 so code shoud perhaps be

my $time = timelocal(0, 0, 0, $d, $m-1, $y - 1900);
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Also, for this particular application, why not set the hash up with the subtraction by one already done?

my %month_num_by_name = (
   JAN => 0,
   FEB => 1,
   ...
);
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Cheers,

JohnGG

Update: davorg and ikegami have pointed out that timelocal() does accept dates like 2007 without first subtracting 1900, although it does the right thing if you do the subtraction as well. ikegami also explained his excellent reason for doing the month the way he does.

I think timelocal() wants the year to be years since 1900

That would make sense. But the documentation says:

Strictly speaking, the year should also be specified in a form consistent with localtime(), i.e. the offset from 1900. In order to make the interpretation of the year easier for humans, however, who are more accustomed to seeing years as two-digit or four-digit values, the following conventions are followed:

• Years greater than 999 are interpreted as being the actual year, rather than the offset from 1900. Thus, 1964 would indicate the year Martin Luther King won the Nobel prize, not the year 3864.

• Years in the range 100..999 are interpreted as offset from 1900, so that 112 indicates 2012. This rule also applies to years less than zero (but see note below regarding date range).

• Years in the range 0..99 are interpreted as shorthand for years in the rolling "current century," defined as 50 years on either side of the current year. Thus, today, in 1999, 0 would refer to 2000, and 45 to 2045, but 55 would refer to 1955. Twenty years from now, 55 would instead refer to 2055. This is messy, but matches the way people currently think about two digit dates. Whenever possible, use an absolute four digit year instead.

The scheme above allows interpretation of a wide range of dates, particularly if 4-digit years are used.

--


<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg

I think timelocal() wants the year to be years since 1900

It accepts both.

why not set the hash up with the subtraction by one already done?

I like $m having a natural value like $d (1..~31) and $y (19xx) do. I always follow localtime and gmtime with $m++; $y += 1900;, and I always specify $m-1 for timelocal and timegm. Not seeing $m-1 raises alarms in my head.

The above advice about Time::Local is good, but if it weren't, your best option would be to effectively copy the code you need from one of the modules you listed.

If you were to consider doing it yourself, don't forget to think about whether you need to take account of: timezones (numeric), timezones (named), leap years, leap seconds, daylight savings time (in all the different timezones, changing over the years) and how comprehensive your test suite needs to be. I think timezones possibly also move on a scale of decades.

Also don't forget to think about whether someone else will be calling your code for similar purposes but who does need to worry about such things.

(The second rule of coding club is "never implement your own character escaping/unicode/charset conversion code").

The third rule is "don't write your own HTML parsing or templating code"

The fourth rule is "don't write your own XML parsing code".

Don't forget, "don't write your own encryption/hashing code"

Don't forget leap years...

and that (among other things) is why its wiser to use established modules when you can.

---

just another cpan module author

#! /usr/local/bin/perl

use Time::Local;

my $timestring = timelocal(0,0,0,31,0,2007);
print $timestring,"\n";
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1170230400
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If you have Time::Piece, just use its strptime function to parse a time string and return a Time::Piece object.

Update: I missed the "without" in your query. If you don't want to use Time::Piece, go with ikegami's advice or install DateTime and DateTime::Format::Strptime.

$ date --date=31-JAN-2007
Wed Jan 31 00:00:00 CET 2007
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$ date --date=31-JAN-2007 +%s
1170198000
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Date::Manip is very powerful. But there are now better ways to deal with dates and times in Perl. And even the author of Date::Manip says that you shouldn't use it most of the time.

--


<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg

I'd like to echo the praise for DateTime, but also note that Date::Manip is still quite useful as DateTime::Format::DateManip due to it's very liberal parser.
-nuffin
zz zZ Z Z #!perl

Hi,

Really it was very useful. Have a method in Date::Manip ie; $date = Date_NextWorkDay($date,$off ,$time); very useful. Its easy.

But had a problem here. Consider if I am adding 10 to a date that falls on saturday or sunday then the next working day must be similar to that when I add 10 working days with a date that falls on Friday.

But it doesnt happens like that with Date::Manip

I am not sure whether I have some mistake in understanding. But anyway fixed the problem by checing whether is a working day if yes then add 10 else add 9

Thanks