How to compare time in perl

[abhishes]

Hello Perl Monks!

I am parsing a file where I find strings of the following pattern 2003/02/05 17:32:06.179

I am able to extract the year, month, day, hour, minute, second and millisecond from this string using a regular expression.

But if I have two such strings how to find out which of the two is smaller. Is there a speedy way to compare two such strings for time.

Thanks for your help in advance.

regards,
Abhishek.

[mojotoad]

You don't have to parse the dates. Since the strings are a) constant width and consistently formatted, and b) organized left-to-right in order of granularity, you can simply use a string comparison. Like so:

#!/usr/bin/perl

@data = <DATA>;
chomp @data;

foreach (sort { $a cmp $b } @data) {
  print "$_\n";
}


__END__
2003/02/05 17:32:06.179
2003/02/05 17:32:06.159
2003/01/05 17:32:06.179
1999/01/05 17:32:06.179

When run this prints:


1999/01/05 17:32:06.179
2003/01/05 17:32:06.179
2003/02/05 17:32:06.159
2003/02/05 17:32:06.179

Matt

[tachyon]

The equal width and 0 packing of single digits is vital as this will choke cmp:

2003/02/05 2:32:06.179
2003/02/05 17:32:06.179
2003/02/05 20:32:06.159

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

[demerphq]

Even if they aren't to begin with he can normalize them first:

  
  $time=~s{
           #$1    $2    $3      $4    $5    $6     $7
           (\d+)/(\d+)/(\d+)\s+(\d+):(\d+):(\d+)\.(\d+)
          }
          {
           sprintf '%04d/%02d/%02d %02d:%02d:%02d.%3d',
                    $1,  $2,  $3,  $4,  $5,  $6,  $7
          }xe
      or die "Failed to normalize '$time'\n";

--- demerphq
my friends call me, usually because I'm late....

[valdez]

You can use Date::Calc to parse time strings and compare them.

Ciao, Valerio

[Nitrox]

Use the site's search to take a peek at existing nodes that cover this.

-Nitrox