in reply to Bracketing Substring(s) in the String

The problem is that once you've added the brackets, index doesn't match anymore. Regular expressions can deal with this more easily. This code allows optional brackets between letters to find the substrings, then it "de-nests" the brackets to get the results you give above. 
sub put_bracket
{
    my    ($str,$ar)    = @_;

    foreach my $subs ( @$ar  )
    {
      # Construct a regexp with [\[\]] between all the letters
      my $newsub = join('[\[\]]?',split(//,$subs));
      $str =~ s/($newsub)/[$1]/g;
    }

    # Now de-nest the brackets in the string
    my $depth = 0;
    my $newstr = '';
    foreach my $c (split(//,$str))
    {
      if ($c eq "\[") {
        $newstr .= $c
        if ($depth++ == 0);
      } elsif ($c eq "\]") {
    $newstr .= $c
        if (--$depth == 0);
      } else {
    $newstr .= $c;
      }
    }

    print "$newstr\n";
    return ;
}

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Re^2: Bracketing Substring(s) in the String
by monkfan (Curate) on Oct 28, 2005 at 07:16 UTC
    Dear sgifford,
    First of all I want to apologize for having have to come back to you to ask this question after some time.

    Since your solution above is so important to me, I need to turn to you for this.
    I truly don't know how to go about it. I hope you won't mind.

    Your code above provide 99% correct solutions, except the following case.
    Example 1: 
    #Given:
my $s5 ='CTGGGTATGGGT';           
my @a5 = qw(GTATG TGGGT);

    [download]
    Your code above returns 
    C[TGGGTATGGGT]

    [download]
    Instead of this the correct one: 
    CTGG[GTATGGGT]

    [download]
    The explanation is as follows TGGGT occur twice in $s5. 
    $s5 = "CTGGGTATGGGT";
        TGGGT
           GTATG      --
                        |--- Only this two satisfy.
              TGGGT   --     Since it follows order 
                             and delim of the given array.

    [download]
    Now why the latter is the correct answer. It is because in the array @a5 = qw(GTATG TGGGT), the string "TGGGT" comes after "GTATG", thus the bracketed region should also follow the order of the given array and the span delimited also by the array. By that I mean, the bracketed regions -- be it disjointed or overlapped -- should always start with first element of the array and end with the last element of the array.

    Let me give another examples, hope it clarifies.
    Read more... (2 kB)
    I would also need to state that the size length of the string in the array is always fixed. In our examples they are always of length 5.

    Is there a way I can modify your code above so that it can handle such case? Hope to hear from you again. I'll try not to bother you again after this.

    Read more... (931 Bytes)
    Update 2 : I think I've got the solution. Thanks so much sgifford, sorry for the trouble.
    Read more... (556 Bytes)

    Regards,
    Edward
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