TimeZone Assistance Requested

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

Dear PerlMonks, Please help me. This is my first post on SOPM so beg you forgive any indiscretions.
The perl code I have managed to "put together" is not giving me the right answers. Here is a data sample that I want it to process:

20050526~18:15:06 GMT
20040401~01:12:02 GMT
20060201~00:59:01 GMT
20060401~01:01:01 EST
20040201~10:10:01 -0600
20010901~04:23:05 -0400
20050526~18:15:06 GMT
20040401~01:12:02 GMT
20000101~00:59:01 -0200
19841223~04:22:06 MST
[download]

And here is the perl code cleaned up a bit with PerlTidy

#!/usr/bin/perl -w
use strict;
use Date::Manip;
Date_Init("TZ=EST");    #set TimeZone to Eastern Daylight Savings Time
{
    my $input = $ARGV[0];    #returns filename from command line
    my $thetmz;              #time zone for that line
    my ( $date, $time);      #from file

    chomp $input;                       #strip the carriage return

    sub convertthetmz {
        $datetime = ( "$date" . "$time" )
          ;    #$date and #time from subroutine call and concats them
        $converteddate = ParseDate("$datetime");    #date-time strng
        $converteddate =Date_ConvTZ("$converteddate", $thetmz, "EST" )
          ;    #converts from any tmz to EST
        print("$converteddate~$from~$to\n");
    }

    open( DATAFILE, "$input" )
      || die("Can not open $input:!\n");    #access the file

    while (<DATAFILE>) {
        chomp $_;
        ( $date, $time) = split( "~", $_ );  #split date/time 

        my $testfortmz = substr $time, -3;    #last 4 chars of str
        if ( "$testfortmz" == "-0400" ) {
            $thetmz = "AST";

            convertthetmz( $thetmz, $date, $time, $from, $to );
        }
        elsif ( "$testfortmz" == "-0600" ) {
            $thetmz = "CST";
            convertthetmz( $thetmz, $date, $time, $from, $to );
        }
        elsif ( "$testfortmz" =~ " GMT" ) {
            $thetmz = "GMT";
            convertthetmz( $thetmz, $date, $time, $from, $to );
        }

        else    #this is need to work for some reason
        {
            my $nochangedate;
            $nochangedate = ( ParseDate("$date.$time") );
            print("$nochangedate~$from~$to\n");
        }

    }
    close(DATAFILE);
}
[download]

The result that I get with the above data sample is the following:

2005052613:15:06
2004033120:12:02
2006013119:59:01
2006040101:01:01
2004020112:10:01
2001090102:23:05
2005052613:15:06
2004033120:12:02
1999123121:59:01
1984122306:22:06
[download]

Some of these are correct but others are I believe wrong.
Shouldn't 20040201~10:10:01 -0600 be 2004020111:10:01 EST since there is only 1 hour difference between -600 and -0500?
Obviously I did something wrong. I would greatly appreciate your assistance! Thank you kindly!

Comment on TimeZone Assistance Requested Select or Download Code

Replies are listed 'Best First'.
Re: TimeZone Assistance Requested by almut (Canon) on Jul 28, 2007 at 03:07 UTC
First, welcome at the Monastery. There are a couple of issues with your code, but as it's time to go to bed in my local TZ, I hope some other kind monks will point them out :) Anyhow, if the idea is to convert those dates (with any TZ) into EST, the whole thing can be simplified considerably, because Date::Manip already does most of the magic while parsing the input string... #!/usr/bin/perl -w use strict; use Date::Manip; Date_Init("TZ=EST"); # target TZ # use your filehandle here instead of DATA while (my $date_anyTZ = <DATA>) { chomp $date_anyTZ; # get rid of '~' to make date parseable by Date::Manip $date_anyTZ =~ tr/~/ /; my $date_EST = UnixDate(ParseDate($date_anyTZ), "%Y-%m-%d %H:%M:%S + %Z"); printf "%-24s --> %s\n", $date_anyTZ, $date_EST; } __DATA__ 20050526~18:15:06 GMT 20040401~01:12:02 GMT 20060201~00:59:01 GMT 20060401~01:01:01 EST 20040201~10:10:01 -0600 20010901~04:23:05 -0400 20050526~18:15:06 GMT 20040401~01:12:02 GMT 20000101~00:59:01 -0200 19841223~04:22:06 MST [download] Prints 20050526 18:15:06 GMT --> 2005-05-26 13:15:06 EST 20040401 01:12:02 GMT --> 2004-03-31 20:12:02 EST 20060201 00:59:01 GMT --> 2006-01-31 19:59:01 EST 20060401 01:01:01 EST --> 2006-04-01 01:01:01 EST 20040201 10:10:01 -0600 --> 2004-02-01 11:10:01 EST 20010901 04:23:05 -0400 --> 2001-09-01 03:23:05 EST 20050526 18:15:06 GMT --> 2005-05-26 13:15:06 EST 20040401 01:12:02 GMT --> 2004-03-31 20:12:02 EST 20000101 00:59:01 -0200 --> 1999-12-31 21:59:01 EST 19841223 04:22:06 MST --> 1984-12-23 06:22:06 EST [download] which looks OK to me.	[reply] [d/l] [select]
Re^2: TimeZone Assistance Requested by Knoperl (Acolyte) on Jul 30, 2007 at 14:42 UTC
Thank you Almut for the code and everyone else for your assistance. I worked on it and it works good. Here is the code: #!/usr/bin/perl -w use strict; use Date::Manip; Date_Init("TZ=EST"); # { my $input =$ARGV[0]; #returns filename from command line my $date_anyTZ; chomp $input; #strip the carriage return open (DATAFILE, "$input")\|\| die ("Can not open $input:!\n"); #access the file while (my $date_anyTZ=<DATAFILE>) { chomp $date_anyTZ; # get rid of '~' to make date parseable by Date::Manip $date_anyTZ =~ tr/~/ /; my $date_EST = UnixDate(ParseDate($date_anyTZ), "%Y-%m-%d %H:%M:%S %Z"); printf "%-24s --> %s\n", $date_anyTZ, $date_EST; } close (DATAFILE); } [download]	[reply] [d/l]
Re: TimeZone Assistance Requested by Anonymous Monk on Jul 28, 2007 at 03:05 UTC
http://en.wikipedia.org/wiki/Eastern_Standard_Time `* Eastern Standard Time - three separate time zones use this name: o the Australian time zone at UTC+10 o the Brazilian Eastern time zone at UTC-3 o the North American time zone at UTC-5 * European Summer Time - the daylight-saving time used in Europe.` [download]	[reply] [d/l]
Re: TimeZone Assistance Requested by Anonymous Monk on Jul 28, 2007 at 02:44 UTC
You're parsing your timestamps wrong `perl -e ' die substr q!012345678!,-3 ' 678 at -e line 1` [download]	[reply] [d/l]