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

i can't figure this out, and I know this must exist in perl either as a construct, or a print/sprintf method...


I'm looking for an idiomatic way to essentially print an "a" followed by 5 "!" characters

ie: print ( "a" . ( "!" * 5 ) )

does that make sense? how the hell do i do this ?

Replies are listed 'Best First'.
Re: repeat characters in text
by cog (Parson) on May 02, 2007 at 17:44 UTC
    print ( "a" . ( "!" x 5 ) )

    That'll do the trick O:-)

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Re: repeat characters in text
by Albannach (Monsignor) on May 02, 2007 at 17:46 UTC
    You have the right idea, you just need a different operator - print 'a', '!' x 5; will do it. Though Perl doesn't care, I prefer not to use double quotes unless I expect interpolation to be taking place.

    --
    I'd like to be able to assign to an luser

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      You have the right idea, you just need a different operator - print 'a', '!' x 5; will do it. Though Perl doesn't care, I prefer not to use double quotes unless I expect interpolation to be taking place.
      print "a@{['!' x 5]}";  # :-)

      [download]
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Re: repeat characters in text
by johngg (Canon) on May 02, 2007 at 19:49 UTC
    Slightly OT but I noticed that two solutions print a string concatenation while another supplied a list of strings to print. I wondered if there was any performance difference between the two. It seems that using a list is consistently about 10% faster. Here's the benchmark code.

    use strict;
use warnings;

use Benchmark q{cmpthese};

my $nullFile = q{/dev/null};
open my $nullFH, q{>}, $nullFile
   or die qq{open: $nullFile: $!\n};

my $rcConcat = sub
   {
       print $nullFH q{a} . q{!} x 5 for 1 .. 10000;
   };

my $rcList = sub
   {
       print $nullFH q{a}, q{!} x 5 for 1 .. 10000;
   };

cmpthese (-3,
   {
      Concat     => $rcConcat,
      List       => $rcList,
   });

close $nullFH
   or die qq{close: $nullFile: $!\n};

    [download]

    and the output from 10 runs.

    Read more... (1185 Bytes)

    Cheers,

    JohnGG

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Re: repeat characters in text
by GrandFather (Saint) on May 02, 2007 at 20:53 UTC

    "Multiple exclamation marks are a sure sign of a diseased mind." (Terry Pratchet: Eric). ;)

    DWIM is Perl's answer to Gödel
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Re: repeat characters in text
by artist (Parson) on May 02, 2007 at 19:00 UTC
    Without parenthesis and double quotes. 
    print 'a'.'!'x5;

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    --Artist
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