Here's one way.

$_="alpha beta beta gamma gamma gamma";
while (s/((\w+)\s\2)/$2/) {};
print $_;
[download]

the second line does something that may not be obvious to everyone, and seems to duplicate /g 's functionality. However, since you've (seemingly) got 3 gamma in a row, writing

$_="alpha beta beta gamma gamma gamma";
s/((\w+)\s\2)/$2/g;
print $_;
[download]

Will leave you with an extra gamma. Using the 'useless' while loop allows the regex to check for multiple duplicates.

As for the regex you tried $string =~ s/(\w+)(.*)\b\1/$1 $2/sig;, we have :

• one or more word characters (\w+)
• zero or more characters of any class (.*)
• a word boundry
• the result of the first match
  The \w+ and the .* don't play nicely together, and this may be what's causing problems.

  ---

  In reply to Re: most efficient regex to delete duplicate words (boo) by boo_radley
  in thread most efficient regex to delete duplicate words by Anonymous Monk

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