Shell Programming and Scripting

I have the following Perl snippet:

Code:

# get datetime
@dt = gmtime();
$strdate = 1900 + $dt[5] . addleadingzero(++$dt[4]) . addleadingzero($dt[3]) . addleadingzero($dt[2]) . addleadingzero($dt[1]) . addleadingzero($dt[0]);

# write to file
$outfile = $strdate . ".txt";
getstore($url, $outfile) or die "Error: Unable to get page $url";

sub addleadingzero {
  return $_[0] < 10 ? "0" . $_[0] : $_[0];
}

The value of $url is not important at this stage, any webpage will do. This code downloads a webpage and the filename is the current date and time (see link removed). I am concerned about the addleadingzero function, because it is called often and I would prefer to use map(), but that is impossible because of year ($dt[5]). How can I make this code more efficient/terse?

Thanks in advance

1) Write addleadingzero() to handle an array and pass all the values (except year) to it. Return the array, then use it, eg

my (@myarray) = ($dt[4], $dt[3], ... etc);
my $outfilename = addleadingzero(@myarray); #returns @result, elements all properly padded....
$outfilename = $year . $result[4] . $result[3] . $result[2] .... etc.

you call addleadingzero() only once for each web-page...

2) You could try setting the year separate from the rest (different variable) then use map on the rest of them, concatenate at the end... More steps, but you cutout addleadingzero() altogether. You'd have to benchmark both and see which is faster....

3) Instead of checking numeric value of $gmtime[...] test it's length() as string and pad with "0", etc. Same as you are doing, but I suspect this one would be slower unless perl's string parsing is more efficient than its numeric... Ya just never know!!!

4) You could use map on all of them... I think you can do stuff like...

(@dt) = ($gmtime[5], $gmtime[4], ... etc, the ones you want);
(@result) = map { if (length($_) < 3 {
#process all but year
} else {
# process year
} } @dt;

The function should do all the date formatting and return the string ready to use. And don't use concatenation when simple string constructors will suffice.

Code:

# get datetime
$strdate = format_date((gmtime ())[0..5]);
# write to file
getstore($url, "$strdate.txt") or die "Error: Unable to get page $url";

sub format_date {
   my @t = @_;
   ++$t[4];
   $t[5]+=1900;
   for (@t[0..4]) {
      $_ = $_ < 10 ? "0$_" : $_;
   }
   return "$t[5]$t[4]$t[3]$t[2]$t[1]$t[0]"; 
}

Note that the link in your post is to a well known pirate website. Please do not post links to that website anymore. Thank you.

Thank you for your suggestions. Ran a few experiments and came up with the following, which at least meets the terseness standard:

Code:

# get datetime
$strdt = strftime "%Y%m%d%H%M%S", gmtime;

# write to file
$outfile = $strdt . ".txt";
getstore($url, $outfile) or die "Error: Unable to get page $url";

It requires use POSIX qw(strftime);

Note that this solution does not require the use of the subroutine addleadingzero.