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

Greetings Fellow Monks,

I have a small substitution problem. I've searched extensively on google, on the super search and tried numerous different test but I just can't get it right.

Let's say I have a text file that contains normal and special 'perl' characters. I would like to remove some detail...

Example of my file:

ZZ<<;ght;''d;\r\n\t\t\t\t\t;$_;LicBpack;'c*'y=eval;perl$@pop&&die@;D9

I would like to discard all the following:

y<<;''\r\n$_pack$_'c*'=eval@&&die

or if it's more readable:

y << ; '' \r \n $_ pack $_ 'c*' = eval @ && die

All suggestions welcome . . .

Replies are listed 'Best First'.
Re: String Substitution...
by BrowserUk (Patriarch) on May 16, 2008 at 00:59 UTC

    Does this produce the required result? 

    $s = q[ZZ<<;ght;''d;\r\n\t\t\t\t\t;$_;LicBpack;'c*'y=eval;perl$@pop&&d
+ie@;D9];;

$s =~ s[$_][]g for map quotemeta, 
    qw[ y << ; pack = eval @ && die], 
    '\n', '\r', "'c*'", "''", '$_';;

print $s;;

ZZghtd\t\t\t\t\tLicBperl$popD9

    [download]
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
      Thank you to all!

      Your wisdom has enlightened me. I tested the other solutions and they seemed to work, but I went with the code from BrowserUk, slim-line and easy to tweak to my requirements.

      My big problem was just to avoid the "map quotameta" and special characters!

      I am a happy monk! :-)

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Re: String Substitution...
by toolic (Bishop) on May 16, 2008 at 00:59 UTC
    Are you familiar with regular expressions? If not, read through perlre and perlreftut. Using the substitution operator is a common way to remove strings. This should get you started: 
    use strict;
use warnings;

my $str = q{ZZ<<;ght;''d;\r\n\t\t\t\t\t;$_;LicBpack;'c*'y=eval;perl$@p
+op&&die@;D9};
$str =~ s/\by\b//g;
$str =~ s/\beval\b//g;
$str =~ s/\bdie\b//g;
$str =~ s/\\(n|r)//g;   # alternation
print $str, "\n";

    [download]

    prints: 

    ZZ<<;ght;''d;\t\t\t\t\t;$_;LicBpack;'c*'=;perl$@pop&&@;D9

    [download]

    Give it a try. If you still can not solve your problem, post some code that you have tried, and ask detailed questions.

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Re: String Substitution...
by graff (Chancellor) on May 16, 2008 at 05:49 UTC
    Is this the sort of result that you want? 
    my @trash = qw/y << ; '' \r \n $_ pack 'c*' = eval @ && die/;

my $src = qw/ZZ<<;ght;''d;\r\n\t\t\t\t\t;$_;LicBpack;'c*'y=eval;perl$@
+pop&&die@;D9/;

for my $kill ( @trash ) {
    $src =~ s/\Q$kill\E//g;
}

print $src, "\n";

    [download]
    The result I get when I run that is: 
    ZZghtd\t\t\t\t\tLicBperl$popD9

    [download]
    But it's quite possible that I don't understand your question.
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