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

I'm having a hard time understanding text manipulation in perl. I want to strip characters from the end of each line in a text file. What operation can strip a certain character/characters from a line / string?

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RE: Stripping characters from strings
by Adam (Vicar) on Oct 30, 2000 at 00:02 UTC
    AgentM had pretty much the complete list (except chop). Your question, however, is not really specific enough to do more then point you at these documents. But I suspect, rather... HOPE, that you looked at the library before posting your question and have therefor seen these documents (chop,chomp,tr,s) so you probably wanted an example. Lets see: 
    use strict; #Always!

my $string = "This is a test string. 123\n";

chomp($string); # removes the "\n" from the end of $string.
chomp($string); # no-op. chomp only removes white-space: \t, ' ', \n, 
+etc...
chop($string);  # removes the '3' from the end of $string.
chop($string);  # removes the '2'... get the idea?
print $string, $/; # print the string, and a new-line.

$string =~ s/a //; # replaces an appearance of 'a ' with ''
print $string, $/; # print the string, and a new-line.
                   # should read: "This is test string. 1"

$string =~ tr/.//d; # remove all periods.
print $string, $/;

$string =~ s/.$//; # removes the last char. slower then chop.
$string =~ s/..$//; # removes the last two characters.

my $n = 6;
$string =~ s/.{$n}$//; # removes the last $n characters.
print $string, $/;

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Re: Stripping characters from strings
by AgentM (Curate) on Oct 29, 2000 at 22:36 UTC
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Re: Stripping characters from strings
by TGI (Parson) on Oct 30, 2000 at 10:51 UTC
    Also checkout substr. Setting the second argument to a negative number (-1) and the fourth (optional) argument to '' can achieve the same thing, or you can use it like an lvalue and assign a value to it. 
    my $foo="foo";
my $bar=substr($foo, -1, 1, '');
print "Foo: $foo\tBar: $bar\n";
# or
substr($foo,-1)=''; 
print "Foo: $foo\n";

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    Results:
Foo: fo        Bar: o
Foo: f

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Re: Stripping characters from strings


by moen (Hermit) on Oct 29, 2000 at 23:15 UTC




    You could do something like

    s/.$//g;
    
This means:
substitute(s/) 
any one character(.) 
counting from the end ($) 
with nothing (//) 
and at all possible matches(g).

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      Is the g needed in this case?  Wouldn't this only match 
the end of line once?
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        With an anchor that isn't within an alteration, "g" is 
pretty useless.  I'm not near a perl with Debugging turned on
so I can't tell you if it's a no-op, but I do know it isn't
a dangerous thing to have on there, just useless. =)

        Update... And what merlyn said below. (yeesh $*)

        -- 
        
$you = new YOU;
        
honk() if $you->love(perl)
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RE: Stripping characters from strings


by ashok (Sexton) on Nov 02, 2000 at 23:58 UTC




    #Split a string into characters
$_ = "Ashok kumar";
@chars = split(//,$_);
@chars = reverse @chars;#@chars will have "ramuk kohsA"

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RE: Stripping characters from strings


by ashok (Sexton) on Nov 03, 2000 at 00:00 UTC




    #Split a string into characters

    $_ = "Ashok kumar";
@chars = split(//,$_);
@chars = reverse @chars;#@chars will have "ramuk kohsA"

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