Maybe it helps if you think about your question in another way?

It sounds to me as if you want to match all strings that start with a sequence of zeroes (or possibly none at all), then the string "11", then possibly some more ones, and then possibly zeroes. This should be easily writeable as a regular expression requiring no special features beyond *.

Can't you just do this?

if($string =~ m/111/){

or have I misunderstood the question?

cheers, Chris

I do not understand your specification. You state that I want only the patterns that has more than 2 consecutive 1's in the string, no all 0's, no "010110" cases.

Please elaborate what you mean by "no all 0's" (a string that has more than 2 consecutive 1's can not have all 0's). Also what do you mean by "no '010110' cases"? ("010110" does not have more than 2 consecutive 1's).

You say that the output should be "01110","111". I assume you meant that "111" should be "1111" since "111" is not in the array.

Also please explain why "01001110" should not match. It contains 3 consecutive 1's.

The following regular expression works for your listed requirements (although I suspect that the requirements are not exhaustive).

if($string =~ /([01]*111[01]*)/){
    print "$string\n"
}
#output
#01110
#1111
#01001110
[download]

I, also, do not understand the OP, but zeroing in on the "I want only the patterns that has more than 2 consecutive 1's ..." portion as zek152 has, I would code the regex slightly differently (I don't understand the  [01]* bits):

>perl -wMstrict -le
"my @strings = qw(0110 1 11 01110 001 100 1111 01001110);
 my @three_or_more = grep { m{ 1{3} }xms } @strings;
 printf qq{'$_' } for @three_or_more;
"
'01110' '1111' '01001110'
[download]

If so, in additional to AnomalousMonk's grep suggestion, several of the others above are solutions or near solutions with the addition of capturing parens:

#!/usr/bin/perl
use strict;
use warnings;
use 5.012;

my @captures;
my $capture;
my $string;

my @strings = qw/0110 1 11 01110 001 100 1111 01001110/;
for $string(@strings) {
    if ( $string =~ /^(.*?1{3}.*)$/ ) {
        push @captures, $1;
    }
}
for $capture(@captures) {
    say $capture;
}
[download]

which produces:

01110
1111
01001110
[download]

I think what you want is /^0*1{3,}0*$/.

Second Edit: After having re-read the question several times, I think what you might want is /^(0|1{3,})*1{3,}(0|1{3,})*$/

Sorry, for the confusion. What I mean is- a string could have several different possible combinations of "0" and "1" of different lengths. Out of all possibilities, I need to extract strings with more than 2 consecutive 1's, irrespective of whether they have 0's in start (eg., 0111) or end (e.g., 1110) or both (e.g., 01110, 00111100) or no 0's at all (eg., 111). In sporadic cases such as 00111011' or 0111001111 have more than 2 consecutive 1's, but also has 1's separated by 0's in other locations, however as it qualifies the condition it should be output

After looking at the clarification of Re: matching pattern question?, I still feel that the  /1{3}/ regex of Re^2: matching pattern question? (or its equivalent) is both necessary and sufficient. I don't understand the purpose of all the other bits that have been added on.

I'm pretty sure I got it above with /^(0|1{3,})*1{3,}(0|1{3,})*$/. Does that work as you expect?