Question

I want to match two different string and output should come in $1 and $2,
According to me in this example, if $a is ‘xy abc’, then $1 should be ‘xy abc’ and $2 should ‘abc’, but ‘abc’ part is coming in $3.
Can you please help me to writing a regex in that $1 should have whole string and $2 should
have second part.
I am using perl 5.8.5.

my @data=('abc xy','xy abc');
foreach my $a ( @data) {
    print "\nPattern= $a\n";
    if($a=~/(abc (xy)|xy (abc))/) {
        print "\nMatch: \$1>$1< \$2>$2< \$3>$3<\n";
    }
}

Output:

perl test_reg.pl

Pattern= abc xy

Match: $1>abc xy< $2>xy< $3><

Pattern= xy abc

Match: $1>xy abc< $2>< $3>abc<

Answer 1

Because only one of captures $2 and $3 can be defined, you can write

foreach my $item ( @data) {

  print "\nPattern= $item\n";

  if ($item=~/(abc (xy)|xy (abc))/) {
    printf "Match: whole>%s< part>%s<\n", $1, $2 || $3;
  }
}

which gives the output

Pattern= abc xy
Match: whole>abc xy< part>xy<

Pattern= xy abc
Match: whole>xy abc< part>abc<