in reply to Re: Simple date and time manipulation
in thread Simple date and time manipulation

Ok, I went through the replies just now, and did some google also. For my need I actually do not need to use any modules. I have a very simple requirement! Here is the code I wrote. In this I have put incrtime as 1 sec, but I can put any number of seconds I want, so no issues there!
#!/usr/bin/perl use strict; my $lat = 23.438; my $slon= 68.000; my $elon= 90.000; my $clon = $slon; my $incrlon= 0.01; my $time = time; my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime($ +time) ; my $incrtime=1; my $printmon; my $printyear; open OUTFILE,">tropic_of_cancer.gpx" or die \"Cannot open file for wri +ting\n"; print \"Printing Header...\n"; print OUTFILE "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"n +o\"?>\n"; print OUTFILE "<gpx version=\"1.1\" creator=\"MakeTropic\" xmlns=\"htt +p://\" xmlns:xsi=\" +MLSchema-instance\" xsi:schemaLocation=\" +X/1/1\">\n"; print OUTFILE "<trk>\n"; print OUTFILE " <name>Tropic of Cancer</name>\n"; while ($clon < $elon) { $printmon = $mon+1; $printyear = $year+1900; print OUTFILE " <trkseg>\n"; printf OUTFILE (" <trkpt lat=\"%.3f\" lon=\"%.3f\">\n", +$lat,$clon); print OUTFILE " <time>$printyear-$printmon-$mday"." +T"."$hour:$min:$sec"."Z"."</time>\n"; print OUTFILE " </trkpt>\n"; $clon=$clon+$incrlon; $time=$time+$incrtime; ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime( +$time) ; } print OUTFILE " </trkseg>\n"; print OUTFILE " </trk>\n"; print OUTFILE "</gpx>"; close OUTFILE;
It works fast and is tiny.

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Re: Solution found!
by andreas1234567 (Vicar) on Jan 19, 2011 at 10:53 UTC
    It works fast and is tiny.
    I beg to differ. It is both slow and verbose. DateTime is 10 times faster, and Date::Calc is 700 times faster! It is a good habit to Benchmark your code before making bold claims about its performance.
    No matter how great and destructive your problems may seem now, remember, you've probably only seen the tip of them. [1]

      What? You're going to compare 16 lines of unrelated code (which contains a nasty loop) to a single line function and call it a benchmark victory? The OP was looking for a quick date time increment. His solution contained this and plenty of other code not directly related to the date time increment. If you're going to benchmark you won't get very far comparing apples to oranges.

      By my benchmarking, the OP's "equivalent datetime increment" code is 144 times faster than DateTime and nearly as fast as Date::Calc.

      It's a good habit to check that your Benchmark code is equivalent before making bold claims about your Benchmark results.