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Re: front-pad a number with zero's
by japhy (Canon) on Oct 30, 2001 at 23:27 UTC
    That's broken, due to the use of the string comparison operators (like lt) in the place of numerical comparison operators (like <). Also, a while loop can be replaced with math: 
    $string = ('0' x ($wanted - $current)) . $string;

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    But honestly, this is a job for sprintf(): 
    sprintf "%0${len}d", $number;

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    That is, sprintf("%05d", 123) returns 00123.

    _____________________________________________________
    Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
    s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

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      You are a genius! Where did you get this sprintf "%0${len}d", $number; It's saved me a lot of troubles. 06-13-2008 Thank you.
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        Where did you get this sprintf "%0${len}d", $number;
        The sprintf documentation, perhaps? 
        printf '<%06s>', 12;   # prints "<000012>"

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        BTW: The thread you responded to is 7 years old.
        --
        No matter how great and destructive your problems may seem now, remember, you've probably only seen the tip of them. [1]
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Re: front-pad a number with zero's
by Masem (Monsignor) on Oct 30, 2001 at 23:27 UTC
    Why not (simply)?: 
    $string = sprintf( "%05d", $number );

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    -----------------------------------------------------
    Dr. Michael K. Neylon - mneylon-pm@masemware.com || "You've left the lens cap of your mind on again, Pinky" - The Brain
    "I can see my house from here!"
    It's not what you know, but knowing how to find it if you don't know that's important

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(tye)Re: front-pad a number with zero's
by tye (Sage) on Oct 31, 2001 at 00:18 UTC

    To both pad short values and (left)truncate long ones: $str= substr("0"x$len.$str,-$len); is another WTDI.

            - tye (but my friends call me "Tye")
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Re: front-pad a number with zero's
by lhoward (Vicar) on Oct 30, 2001 at 23:27 UTC
    You can do the same thing with sprintf. 
      my $f=sprintf("%05d",123);

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    will put "00123" into $f.
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(Ovid) Re: front-pad a number with zero's
by Ovid (Cardinal) on Oct 30, 2001 at 23:29 UTC

    TIMTOWTDI (though sprintf is faster):

    sub pad_zeros {    
    my $optimal_length = 5;
    my $num = shift;
    $num =~s/^(\d+)$/("0"x($optimal_length-length$1)).$1/e;
    return $num;
}

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    Cheers,
    Ovid

    Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.

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      A regex is overkill here. (If I'm saying it, trust me...) If you're against using sprintf(), just do the math: 
      sub pad {
  my ($num, $len) = @_;
  return '0' x ($len - length $num) . $num;
}

      [download]

      _____________________________________________________
      Jeff[japhy]Pinyan: Perl, regex, and perl hacker.
      s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

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[d/l]

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