PERL Beginners - converting between time and string

Author

converting between time and string

Bnj.S

2006-06-24, 8:01 am

Hello,

I have a file with lots of times in the format "01:22:33,456", where the
numbers after the comma represent the milliseconds.

I would like to reduce all these times by a given offset. I first
thought to convert the string to a sort of date format, and then to do a
minus operation, and then to convert the result back to a string of the
original form. However, I have great difficulties finding how to handle
times and dates. I am sure, however, that there exist a simple way to do
so in perl. Could you please help me and tell me how you would do it?

Thank you and best regards,

Benjamin

Muma W.

2006-06-24, 8:01 am

Dr.Ruud

2006-06-24, 8:01 am

"bnj.s" schreef:

> I have a file with lots of times in the format "01:22:33,456", where
> the numbers after the comma represent the milliseconds.
>
> I would like to reduce all these times by a given offset. I first
> thought to convert the string to a sort of date format, and then to
> do a minus operation, and then to convert the result back to a string
> of the original form. However, I have great difficulties finding how
> to handle times and dates. I am sure, however, that there exist a
> simple way to do so in perl. Could you please help me and tell me how
> you would do it?

What is the smallest (earliest) time value, and is it bigger than the
offset?

If yes:

#!/usr/bin/perl
use strict ;
use warnings ;

use integer ;

sub t2ms
{
$_[3] ||= '' ;
$_[3] .= '0' while length $_[3] < 3 ;
return ( ( $_[0] * 60 + $_[1] ) * 60 + $_[2] ) * 1000 + $_[3] ;
}

sub ms2t
{
$_[3] = $_[0] % ( 1000) ;
$_[2] = $_[0] % ( 60 * 1000) / ( 1000) ;
$_[1] = $_[0] % (60 * 60 * 1000) / ( 60 * 1000) ;
$_[0] = $_[0] / (60 * 60 * 1000) ;
return @_ ;
}

my $qr = qr/(\d\d):(\d\d):(\d\d)(?:,(\d*))?/ ;

my $offset = - t2ms( '00:00:01,234' =~ m/$qr/ ) ;

while ( <DATA> )
{
printf "%02d:%02d:%02d,%03d\n", ms2t( t2ms( m/$qr/ ) + $offset ) ;
}

__DATA__
01:22:33,456
12:34:56,7
23:45:19,001
23:45:19,01
23:45:19,0
23:45:19,
23:45:19

But please check out DateTime::Duration too.

--
Affijn, Ruud

"Gewoon is een tijger."

Mark Harris

2006-06-24, 8:01 am

bnj.s wrote:
> Hello,
>
> I have a file with lots of times in the format "01:22:33,456", where the
> numbers after the comma represent the milliseconds.
>
> I would like to reduce all these times by a given offset. I first
> thought to convert the string to a sort of date format, and then to do a
> minus operation, and then to convert the result back to a string of the
> original form. However, I have great difficulties finding how to handle
> times and dates. I am sure, however, that there exist a simple way to do
> so in perl. Could you please help me and tell me how you would do it?
>
> Thank you and best regards,
>
> Benjamin

Unless I don't quite get what you're asking this seems pretty simple
# string to milliseconds
$refTime = "01:22:33,456"; #as in your example
$refTime =~ /(\d+):(\d+):(\d+),(\d+)/; #capture the elements and assign
$hours = $1;
$minutes = $2;
$secs = $3;
$mili = $4;

#calc milliseconds if needed

$millisec = $mili+($secs*1000)+($minutes*60*1000)+($
hours*60*60*1000);
#reduce minutes by 5
$minutes-= 5;
#format for printing
$outStr = sprintf("%02d:%02d:%02d,%03d",$hours,$minutes,$secs,$mili);
print $outStr;

JupiterHost.Net

2006-06-24, 8:01 am

Hello,

> $refTime = "01:22:33,456"; #as in your example
> $refTime =~ /(\d+):(\d+):(\d+),(\d+)/; #capture the elements and assign
> $hours = $1;
> $minutes = $2;
> $secs = $3;
> $mili = $4;

or much simpler:

my($hours, $minutes, $secs, $mili) = $ref_time =~ m{(\d+)}g;

Note that if it doesn't match then the variable will be undef...

This doesn't look strict or wanrings safe either, please always use

use strict;
use warnings;

Please buy Perl best Practices, you'll love it and your code will be
much more readable (like $ref_time vs $refTime is clearer and less
problem prone...)

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