Perl Regex只匹配1个域名

Question

I'm trying to create a regex which matches the following:

part1@domain.com

part1: where part1 is any 5 digit number from 0-9
part2: [optional] where @domain.com are all domains except @yahoo.com

example: 12345@yahoo.com
I'm not able to find how to insert a conditional into the regex. Now only my regex match digits + domain. Still need to figure out:

1. how to match only the digits
2. conditional to accept all domains except @yahoo.com

Code:

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

my $regex1 = '^(\d{5})([@]([a-zA-Z0-9_-]+?\.[a-zA-Z]{2,6})+?)';

while ( my $line = <DATA> ) {
  chomp $line;
  if ($line =~ /$regex1/)
  {
    print "MATCH FOR:\t$line \n";
  }
}

Sample data:

1234
12345@
12345@tandberg
A12345@tandberg.com
12345
12345@tandberg.com
12345@cisco.com
12345@tandberg.amer.com
12345@tandberg.demo

Answer 1

why not simply first check for yahoo.com and if you get a match go to the next line:

while ( my $line = <DATA> ) {
  chomp $line;
  next if ($line =~ /yahoo\.com$/);
  if ($line =~ /$regex1/)
  {
    print "MATCH FOR:\t$line \n";
  }
}

Answer 2

How about this?

\d{5}(?:@(?!yahoo)[a-zA-Z0-9.]+\.[a-zA-Z]{2,3})?

In expanded form:

\d{5}            # 5 digits
(?:              # begin a grouping
  @              # literal @ symbol
  (?!yahoo\.com) # don't allow something that matches 'yahoo.com' to match here
  [a-zA-Z0-9.]+  # one or more alphanumerics and periods
  \.             # a literal period
  [a-zA-Z]{2,3}  # 2-3 letters
)                # end grouping
?                # make the previous item (the group) optional

(?!yahoo\\.com) is what's called a " negative lookahead assertion ".