Best way to compare date strings

minixman has asked for the wisdom of the Perl Monks concerning the following question:

All i have a question about the best way to compare date strings. I have the following two dates.

my $date1 = "2006/01/03 03:59:59:671";
my $date2 = "2006/01/03 04:00:00:562";
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Now would the best way to get how many seconds / milliseconds there are between them to do. First strip out the 2006 day month as they are the same ? or leave them and do

$date1 =~ s/://g;
$date2 =~ s/://g;
my $ordermilliseconds = $clsendtimestamp - $clrectimestamp;
my $ordersecs = $ordermilliseconds / 1000;
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Comment on Best way to compare date strings Select or Download Code

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Re: Best way to compare date strings by davorg (Chancellor) on Jan 04, 2006 at 12:01 UTC
Use the DateTime family of modules. `#!/usr/bin/perl use strict; use warnings; use DateTime::Format::Strptime; my $fmt = DateTime::Format::Strptime->new(pattern => '%Y/%m/%d %H:%M:% +S:%3N'); my $date1 = $fmt->parse_datetime('2006/01/03 03:59:59:671'); my $date2 = $fmt->parse_datetime('2006/01/03 04:00:00:562'); my $diff = $date2 - $date1; print $diff->in_units('nanoseconds'), "\n";` [download] -- <http://dave.org.uk> "The first rule of Perl club is you do not talk about Perl club." -- Chip Salzenberg	[reply] [d/l]
Re^2: Best way to compare date strings by minixman (Beadle) on Jan 04, 2006 at 12:36 UTC
Strange when i install the mods and run i get. `$ perl test.pl Can't call method "in_units" on an undefined value at test.pl line 22.` [download]	[reply] [d/l]
Re^3: Best way to compare date strings by minixman (Beadle) on Jan 04, 2006 at 12:50 UTC
I downloaed the modules again and installed them, still get strange errors `$ perl test.pl Scalar found where operator expected at (eval 4) line 1, near "%+$nano +second" (Missing operator before $nanosecond?) syntax error at (eval 4) line 1, near "%+$nanosecond"` [download]	[reply] [d/l]
Re^4: Best way to compare date strings by davorg (Chancellor) on Jan 04, 2006 at 16:59 UTC
Re: Best way to compare date strings by derby (Abbot) on Jan 04, 2006 at 15:04 UTC
In the TMTOWTDI mode: #!/usr/local/bin/perl -d use strict; use warnings; use Time::Local; use Time::HiRes qw( tv_interval ); my $date1 = "2006/01/03 03:59:59:671"; my $date2 = "2006/01/03 04:00:00:562"; my $t1 = convert_time( $date1 ); my $t2 = convert_time( $date2 ); my $elapsed = tv_interval( $t1, $t2 ); print $elapsed, "\n"; sub convert_time { my $date = shift; my( $yr, $mo, $dy ) = split( /\//, substr( $date, 0, 10 ) ); my( $hr, $mn, $sc, $mi ) = split( /:/, substr( $date, 11 ) ); my $epoch = timelocal( $sc, $mn, $hr, $dy, $mo-1, $yr-1900 ); [ $epoch, $mi*1000 ]; } [download] -derby	[reply] [d/l]
Re^2: Best way to compare date strings by minixman (Beadle) on Jan 04, 2006 at 16:25 UTC
That looks good	[reply]
Re: Best way to compare date strings by Anonymous Monk on Jan 04, 2006 at 12:49 UTC
my @seconds = (); `for my $date ( $date1, $date2 ) { my @fields = ( split( /:/, $date ); my $frac = pop @fields; my $sec = pop @fields; push @seconds, join( '.', ( $sec, $frac ) ); }` [download]	[reply] [d/l]