how to find a word including same two letter?

[whygh]

in regular expression, how to find a word including same two letter? like hello,wall, google?

 

[mikevh]

$var =~ /(.)\1/;

 

[whygh]

Thanks. I tried it. the result is
1)
$var="hello";
$var =~ /(.)\1/;
print "$var\n";

the output is "hello"
2)
$var="very";
$var =~ /(.)\1/;
print "$var\n";

the output is "very"

3)
$var="hello";
$var =~ /(.)\1/;
print "$&\n";

the output is "ll"

I want to get the whole word which has two same letters.How do I do? By the way, can you tell me the meaning of "\1"

Thanks again

 

[KevinADC]

you can add a condition:

my $var = "hello";
print $var if ($var =~ /(.)\1/);

my $var2 = "test";
print $var2 if ($var2 =~ /(.)\1/);

\1 is whats stored in ()

 

[rharsh]

Take a look at perldoc perlre

 

[TrojanWarBlade]

I thought I'd have a little go for you:

#!/usr/bin/perl -w

use strict;

while(<>) {
  chomp;
  print "$1\n" if(/\b(\w*(\w)\w*\2\w*)\b/);
}

This only finds the first word on the line but it wouldn't be that hard to expand if you need to.

Do you want vowels included as well in this selection?

As in "room"?

Trojan

 

[TrojanWarBlade]

I got bored so I expanded it to do all words on a line.

#!/usr/bin/perl -w

use strict;

while(<>) {
  chomp;
  my @words = split;
  my $found = 0;
  foreach my $word (@words) {
    if($word =~ /\b(\w*(\w)\w*\2\w*)\b/) {
      print "$1 ";
      $found++;
    }
  }
  print "\n" if($found);
}

BTW: You ought to also consider if a capitalised word should be handled such as "Tint". If you need this then you should add the /i switch to the regex.

Trojan

 

[whygh]

Thanks. It get the right result.
but it has a little bit problem,for explample:

test="lolgh";
print "$1\n" if($test=~/\b(\w*(\w)\w*\2\w*)\b/);

it also match.I need just match like "hello,wall,room".


This is another regular experssion,it works.


$var1="20-20-20";
print $var1 if($var1=~/(\d{2})([\W])\1\2\1/);

"\1" is (\d{2})
"\2" is ([\W])

is it right?

 

[TrojanWarBlade]

I take it you want words with ADJACENT letters the same.
You must be very careful to describe EXACTLY what you want.
If so, change the /\b(\w*(\w)\w*\2\w*)\b/ to /\b(\w*(\w)\2\w*)\b/

Yes, your description of \1 and \2 are correct.
That regex will only match digits though and could match all sorts of thing between the numbers.

Trojan.

 

[whygh]

Thanks. really appreciate it .