use strict;

my $exampleinput = q(1 | p1=v1,p2=v2 | p3=v3,p4=v4);

sub processrow( $ $ )
{
    my ( $hashref, $input ) = @_;

    my @condition = split( /\s*\|\s*/, $input );

    my $index = shift( @condition );

    $hashref->{$index} = [ map { { map { $_->[0] => $_->[1]
                                   } map { [ split( /=/, $_ ) ]
                                       } map { split( /,/, $_ )
                                           } $_ } } @condition
                          ];
}

my %examplehash = ();
processrow( \%examplehash, $exampleinput );

{
    use Data::Dumper;
    print( Dumper( \%examplehash ) );
}