Re: fixed length string

s/// can do the job: use .{1,$x} to get the first 1 to $x characters, discarding any after $x, then pack "A$x" to space-pad to $x.

#!perl
use strict;
my $fixlen = 5;
my @words = qw( s so som some somew somewo somewor someword somewords)
+;
foreach my $word (@words) {
  $word =~ s/^(.{1,$fixlen}).*$/pack "A$fixlen", $1/e;
  print ">$word<\n";
}
__END__
>s    <
>so   <
>som  <
>some <
>somew<
>somew<
>somew<
>somew<
>somew<
[download]

Comment on Re: fixed length string Download Code

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Re^2: fixed length string by keszler (Priest) on Jul 05, 2004 at 10:37 UTC
I was curious, so I compared the two one-liners (s/// and sprintf), as follows: #!perl use strict; use Benchmark qw( timethese cmpthese ) ; my $fixlen = 5; my @words = qw( s so som some somew somewo somewor someword somewords) +; my $b = timethese( -5, { srchrep => sub{foreach my $word (@words) { $word =~ s/^(.{1,$fixlen}).*$/pack "A$fixlen", $1/e +; }}, xprintf => sub{foreach my $word (@words) { $word = sprintf "%-$fixlen.${fixlen}s", $word; }}, }); cmpthese $b; __END__ Benchmark: running srchrep, xprintf for at least 5 CPU seconds... srchrep: 5 wallclock secs ( 5.54 usr + 0.00 sys = 5.54 CPU) @ 54 +48.01/s (n=30182) xprintf: 6 wallclock secs ( 6.76 usr + 0.00 sys = 6.76 CPU) @ 20 +874.11/s (n=141109) Rate srchrep xprintf srchrep 5448/s -- -74% xprintf 20874/s 283% -- [download] Looks like sprintf wins the speed test, by a large margin.	[reply] [d/l]
Re^2: fixed length string by calin (Deacon) on Jul 05, 2004 at 12:07 UTC
`my @words = qw( s so som some somew somewo somewor someword somewords) +;` [download] Just a tip for the lazy... `my $str = 'somewords'; local ($\,$,) = ("\n") x 2; print map {substr $str, 0, $_} 1..length($str); # or print map {$str =~ /(.{$_})/} 1..length($str); # or { my $mem; print map {$mem .= $_} split //, $str; } # etc. (Golf?)` [download]	[reply] [d/l] [select]