Thank you for replying. I am very new to this, so sorry for the confusion. I am adding words to a line, but do not want to duplicate. The 2 strings are $words and $w. However, if advertise is one word, I don't want the word "ad" to be left out. My expression is only checking if the 2 words are equal to each other, I need to be checking past the first 2 characters.

If I understood right, you have a list of words in a string and you want to add a word to that string, the new word should not exist already in the words string, am I right till here? If yes then you should do as follows:

# suppose you have:
$line = qw(advanture door tree);
# and $word is:
$word = 'ad';
...

if ($line =~ /\b$word\b/) {
  next;
} else {
  # add $word to the list
}
# only if $word will be exactly 'adventure' or 'door' it will be skipe
+d over
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'\b' is a word boundry like a space a comma (anything that is not a-z, A-Z, 0-9 or '_'), so the regexp in the 'if' statement is exactly what you need.

Hotshot

Let me see if I understand your problem: you have a list of strings, such as "bar", "bartender", and "foobar". You want to get rid of any duplicates, but you have to make sure that "bar" won't match against "bartender" or "foobar".

First solution that comes to mind is to ignore the regex and simply use string eq:

If you really need a regex for some reason, use \s to match whitespace around the word:

Probably better check for word boundaries around the word, as they will also match the beginning and end of string;

next if $word=~/\b$w\b/;
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Or you can use the slightly more longwinded form using alternations that allows $w to start with non-work characters (\b looks at the change between \W to \w not \s and \S):

next if $word =~ /(^|\s)$w(\s|$)/;
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--
integral, resident of freenode's #perl

 if ($words =~ m/\s+bar\s+/){
                 next;
            }
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