@listOfUser = {testuser password1, testuser2 password2, testuser3 password3};

my $username = sometext
my $password = password

use strict; use warnings;
use YAML;

my @users = (
    'testuser password1',
    'testuser2 password2',
    'testuser3 password3',
);

@users = map { my ($u, $p) = split; { user => $u, pass => $p } } @users;

print Dump @users;

for my $elem (@listOfUser) {
    my ($username, $password) = split " ",$elem;
    # do something with $username and $password
}

my %user_password = (
    user1 => 'pass1',
    user2 => 'pass2',
    ....
);

for my $user ( keys %user_password ) {
    print "username: $user, password: $user_password{$user}n";
}