(In perl -de 17:) 
  DB<6> $x = 'helloworldhellohellohihellohiworldhi'

  DB<7> print "$1\n" while $x =~ /(\w+)(?=.*\1.*\1)/g
hello
o
l
hello
h
l
l
o
hi
h
l

[download]

The single letters appear, of course, since they're repeated more than once. We can fix that by requiring \1 to be at least 2 characters long... 

  DB<8> print "$1\n" while $x =~ /(\w{2,})(?=.*\1.*\1)/g
hello
hello
hi

[download]
Of course it still finds `world', which appears 4 times.

To autogenerate the regexp: 

sub repeat_finder_re {
  my $n = shift;
  '(\w{2,})(?=' . ('.*\\1'x($n-1)) . ')'
}

[download]

In reply to Re: Pattern Finding by ariels
in thread Pattern Finding by artist

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