sprintf to zero-pad on the right

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

Newbie sprintf question. I have a string TEST and I want to append zeros so that I have TEST0000.

Trying the following yields 0000TEST:

my $string = 'TEST';
$string    = sprintf "%08s", $string;
[download]

So after reading a bit more, I tried this thinking that the zeros would appear after the string:

my $string = 'TEST';
$string    = sprintf "%-08s", $string;
[download]

But that gives me "TEST " (note the 4 blank spaces instead of zeros). I'm sure I'm missing something obvious.

_{janitored by ybiC: Retitle from "sprintf question" for better search results}

Comment on sprintf to zero-pad on the right Select or Download Code

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Re: sprintf question by matija (Priest) on Mar 15, 2004 at 16:43 UTC
How about `$string.="0" x (8-length($string))`	[reply] [d/l]
Re: sprintf question by kvale (Monsignor) on Mar 15, 2004 at 16:27 UTC
How about avoiding `sprintf` altogether? `my $string = 'TEST'; $string .= '0000';` [download] Update: If you have a variable length string, then use `$string .= '0' x ($fixed_length - length $string);` [download] to pad it to the desired `$fixed_length`. -Mark	[reply] [d/l] [select]
Re: Re: sprintf question by Anonymous Monk on Mar 15, 2004 at 16:33 UTC
Hi Mark, thanks for your reply and I should have explained further. The total length I'm looking for is 8. So if I see a four character string (i.e `TEST`) I know I should append 4 zeros. If I see a three character string, I would append 5 zeros etc. I thought `sprintf` would be a natural choice for this but couldn't get it to work...	[reply] [d/l] [select]
Re: sprintf question by Tomte (Priest) on Mar 15, 2004 at 16:46 UTC
I really don't know if there's not a much better solution, but this does the trick: `reverse(sprintf("%08s", "" . reverse( "TEST")));` [download] regards, tomte Hlade's Law: If you have a difficult task, give it to a lazy person -- they will find an easier way to do it.	[reply] [d/l]
Re: sprintf question by BrowserUk (Patriarch) on Mar 15, 2004 at 19:20 UTC
`$string = 'TEST'; print substr $string . '0'x8, 0, 8; TEST0000` [download] Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "Think for yourself!" - Abigail	[reply] [d/l]
Re: sprintf question by TomDLux (Vicar) on Mar 15, 2004 at 19:08 UTC
I would normally do what matija & kvale suggest. I've also seen code that appends $field_size zeros to the print string, and then taking a substring: `$padding ="0" x $field_size; $padded_string = substring $text . $padding, 0, $field_size;` [download] If you have a humonguous number of fields to output, it might be worth benchmarking the two methods. -- `TTTATCGGTCGTTATATAGATGTTTGCA`	[reply] [d/l]
Re: sprintf question by AcidHawk (Vicar) on Mar 16, 2004 at 08:45 UTC
What about using substr..? `my $strlen = "00000000"; my $string = "TEXT"; substr($strlen, -length($string)) = "$string";` [download] You can then `print "$strlen\n";` ----- Of all the things I've lost in my life, its my mind I miss the most.	[reply] [d/l] [select]
Re: sprintf question by ysth (Canon) on Mar 16, 2004 at 03:37 UTC
`$string = reverse sprintf "%08s", scalar reverse $string;`	[reply] [d/l]