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

Is there a quick and simple way to remove the first two characters of a string?

Replies are listed 'Best First'.
Re: Deleting from front of string
by Moonie (Friar) on Oct 05, 2001 at 02:23 UTC
[reply]
Re: Deleting from front of string
by gryphon (Abbot) on Oct 05, 2001 at 02:31 UTC

    Greetings krose,

    Try the following where 2 is the number of characters you want removed from the 'some string' given:

    print substr('some string', 2);

    -gryphon
    code('Perl') || die;

[reply]
[d/l]
Re: Deleting from front of string
by demerphq (Chancellor) on Oct 05, 2001 at 06:21 UTC
    Frankly im amazed no one else posted this reply 
    my $str='Blah blah blah';
my $removed=substr($str,0,2,"");
print "Removed=$removed and Str=$str\n";

    [download]
    Substr with 4 arguments sets the substr in question to equal the value of the 4th argument. In this case delete it.

    Yves
    --
    You are not ready to use symrefs unless you already know why they are bad. -- tadmc (CLPM)

[reply]
[d/l]

      Also the value that substr returns is an lvalue (i.e. can be assigned to). 

      perl -le '$_ = "foo bar"; substr($_,0,2) = ""; print'

      [download]
[reply]
[d/l]
Re: Deleting from front of string
by tachyon (Chancellor) on Oct 05, 2001 at 02:49 UTC 
    $_ = "just another perl hacker";
$_ = reverse, chop, chop && print scalar reverse;

    [download]

    cheers

    tachyon

    s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

[reply]
[d/l]
      Ah, but what if you had some "evil" string such as: 
      $_ = '10.) just another perl hacker';

      [download]

      -Blake

[reply]
[d/l]
        How about
        
my $i;
print join '', grep $i++>1, split //, '#!just another perl hacker';

        [download]
[reply]
[d/l]
        $_ = '10.) just another perl hacker';
$_ = reverse,chop,chop,print scalar reverse;

        [download]

        Perl a problem for every solution solution for every problem

        cheers

        tachyon

        s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

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[d/l]
(Daddio) Re: Deleting from front of string
by Daddio (Chaplain) on Oct 05, 2001 at 04:10 UTC

    Other than substr, there is always the regex method:

    $_ = "just another perl hacker";
s/^.{2}(.*)$/$1/;
print;

    [download]

    D a d d i o

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[d/l]
[select]
      What happens with this string? 
      $_=qq!\nJ\nu\ns\t another Perl hacker!;

      [download]

      Your regexp fails, because \n is not matched by /./ Nobody have said that the two first characters matches with /./
      Try this
      s/(\w|\W){2}//;

      [download]
      Regards
      Hopes
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[d/l]
[select]
        Very well spotted, Hopes. Dot not matching a newline is such a common mistake it's easy to forget. I'm glad that you noticed it.

        <pedant>

        Actually, it's possible to get dot to match everything by using the /s switch. This also has the benefit that ^ and $ will match the beginning and end of the string, and not at line breaks, which for our purposes here is desirable. See the perlre man page for details.

        Hence $string =~ s/^..//s does what we want, even if we are dealing with newlines. If you don't mind losing clarity, you can even drop the ^ in this situation.

        </pedant>

        Having said all that, the substr method described above would be my recommendation. (It's also likely to be the fastest). ;)

        Cheers,
        Paul

[reply]
      why use $1? 
      s/^.{2}//s;

      [download]
      The s modifier at the end takes care of \n chars as well.

      But substr() is the best way anyway... :)

      .02

      cLive ;-)

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[d/l]
Re: Deleting from front of string
by ambrus (Abbot) on Apr 11, 2006 at 14:29 UTC
[reply]

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