Perl正则表达式可进行多次匹配

Question

I have a file with lines similar to following:

abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1

I want to retain strings up to last ":" and remove all occurrences of abcd1

In the end, I need to have below:

abcd1::101:xyz1,xyz2,xyz3,pqrs1,xyz4

I tried code as below, but for some reason, it is not working. So please help the account name is "abcd1"

sub UpdateEtcGroup {
    my $account = shift;
    my $file = "/tmp/group";

    @ARGV = ($file);
    $^I = ".bak";
     while (<>){
         s#^($account::\d{1,$}:)$account,?#$1#g;
         s/,$//; # to remove the last "," if there
         print;
         }
 }

Answer 1

Don't use a regular expression for this.

use strict;
use warnings;

while (<DATA>) {
    chomp;
    my @parts = split(/:/, $_);
    $parts[-1] = join(',', grep { !/^abcd/ } split(/,/, $parts[-1]));
    print join(':', @parts) . "\n";
}

__DATA__
abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1
abcd2::102:user1,xyz2,otheruser,abcd2,pqrs1,xyz4,abcd2

Output:

abcd1::101:xyz1,user,user1,pqrs1,userblah
abcd2::102:user1,xyz2,otheruser,pqrs1,xyz4

Answer 2

split is the tool for the job, not a regex .

Because split lets you reliably separate out the field you do want to operate on, from the ones that you don't. Like this:

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

my $username = 'abcd1';

while ( <DATA> ) {
   my @fields = split /:/; 
   my @users = split ( /,/, pop ( @fields ) ); 
   print join ( ":", @fields, 
               join ( ",", grep { not m/^$username$/ } @users ) ),"\n"; 
}


__DATA__
abcd1::101:xyz1,user,user1,abcd1,pqrs1,userblah,abcd1