in reply to Adding a TAB after a certain ammount of characters

You can use substr to change a string: 
my $string = "20130204000000000068100836100220130681002002201306880002
+00494";
my $n = -1;
substr $string, $n += 1 + $_, 0, "\t" for 17, 6, 31, 3, 3;
print "$string\n";

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Re^2: Adding a TAB after a certain ammount of characters
by johngg (Canon) on Apr 16, 2013 at 22:20 UTC

    Attacking the insertions in reverse order from the right-hand side means you don't have to increment your position by one for each successive insertion. Swings and roundabouts really but sometimes a useful technique.

    $ perl -Mstrict -Mwarnings -E '
> my $text =
>    q{2013020400000000006810083610022013068100200220130688000200494};
> my @offs = ( 17, 6, 31, 3, 3 );
> my @cums = ( 0 );
> push @cums, $_ + $cums[ -1 ] for @offs;
> substr $text, $_, 0, q{-} for reverse @cums[ 1 .. $#cums ];
> say $text;'
20130204000000000-068100-8361002201306810020022013068800-020-049-4

    [download]

    Here's the code without the PS2 prompt for easier copy'n'paste, as requested by /msg in respect of another post.

    Read more... (499 Bytes)

    I hope this is of interest.

    Cheers,

    JohnGG

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      Hi, I've tried to use it exactly as you put it and I got:

      biancoari@biancoari ~/Desktop $ perl perl1.pl
      String found where operator expected at perl1.pl line 8, near "say $text;'"
      (Might be a runaway multi-line '' string starting on line 1)
      (Missing semicolon on previous line?)
      syntax error at perl1.pl line 8, near "say $text;'"
      Execution of perl1.pl aborted due to compilation errors.

      Besides I have another question what I am trying to modify is a txt file with several lines (like the one on the example, they are all the same) any clue on that?

[reply]

        Please show us your perl1.pl script inside <code> and </code> tags so we can see where you are going wrong. As for working on a multi-line file, calculate the offsets, open your file then do something like

        while ( <$inputFH> )
{
    foreach my $offset ( reverse @cums[ 1 .. $#cums ] )
    }
        substr $_, $offset, 0, q{-};
    }
    print;
}

        [download]

        I hope this moves you forward.

        Update: Code modified to replace for statement modifier with an explicit loop, thanks choroba.

        Cheers,

        JohnGG

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[d/l]
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        syntax error at perl1.pl line 8, near "say $text;'"

        Note the single-quote just after the ; (semicolon) in "say $text;'". This closes the quoted code that began with an opening single-quote just after the -E on the first line of the command line invocation in johngg's reply. Get rid of that closing single-quote if you are running the code from a file and things will probably work better.

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