I know, yet I would like what causes this strange effect. I have atually some more lines in my code and have differnt return formats, so I just want to know, why this is replacing the leading 0 with a space.
It is a bit strange to me, as the minutes are always accepted normally.

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

while ( <DATA> ) {
    chomp;
    print format_time( split " " , $_ ), "\n";
}
sub format_time {
    return sprintf("%.2d:%.2d:%.2d", @_)
}
__DATA__
9 12 54
23 8 7
[download]

In this case I perfectly see that sprintf does the job very well. Only the problem is, that at some other places I will soon have to concatenate strings that cann be only digits, letters, ... a lot of them start with leading 0 that I will need to print out later. I have no clear formatting, at least there are about 12 formats I have seen yet. I do not want to create a regexp for each.

PerlingTheUK,
I do not understand what you are asking. If you would like to parse date/time strings that come in different formats, you should have a look at Date::Manip. If you are asking how to do some sort of templating then please try to rephrase your question. Break the problem into small pieces, put them in a logical order, and then present them to us in a digestible manner.

Cheers - L~R

If I run the code you posted verbatim, except for removing the ..., I get 0905 in the first line. The problem in your code is elsewhere, either in that ... which you're hiding, or in another part completely.

Why would you think a zero character magically turns into a space? Are you sure a zero character was ever added? Try instrumenting your code:

sub format_time{
    my ( $h, $m, $s ) = @_;

    ...

    warn "\$h is now '$h', length " . length $h;
    if ( length( $h ) < 2 ) {
        warn "going to pad with zero";
        $h = "0" . $h; 
    }

    if ( length( $m ) < 2 ) {
        $m = "0" . $m; 
    }

    return $h . $m . $s2;
}
[download]

I am almost certain you will find that the space is already there by the time you get to that conditional and that the second message from inside that code block never gets printed.

Always question your assumptions, and know what your code is doing, instead of programming by coincidence.

And then, when you've found the problem and taken away its lesson, throw away your code and use sprintf.

print "[$h][$m][$s]\n";
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I basically round the times and want to add a 0 in front of the minutes and hours if they have less than 2 chars anyway.

errm... what's wrong with:

:
:   rest of code before...
printf "%0.2d:%0.2d:%0.2d\n",$hour,$min,$sec;
:
: much handwaving
:
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What's $s2?

$s2 is indication for half a second. But that does not have any influence on the result.

Sounds like you're not using strict... doing that might shed some light on the problem (and indeed on unseen and unforseen ones as well).

There is a simpler way:

sub format_time
{
  my ($h, $m, $s) = @_;
  return sprintf "%02d%02d%02d", $h, $m, $s;
}
[download]

I think you probably want to use sprintf rather than what you are doing now.

  sub format_time
  {
     my ( $h, $m, $s) = @;

     return sprinf "%.02d%.02d%.02d", $h, $m, $s;
   }
[download]

/J\