... everything makes sense except the alternative loop examples ...

They were meant to illustrate the Perl style for loop (aka foreach loop), so you would be aware of it. The C style loop actually makes more sense in your program, but that is usually not the case.

The basic idea of the Perl for loop is that it loops over a list of values, aliasing each one to the loop variable in turn. The following should help clarify:

# foreach $variable ( @list_of_values ){ ...
# or
# for $variable ( @list_of_values ){ ...

# $variable is aliased to each successive item in list
# @list_of_values can be a literal list, an array or an
# expression that evaluates to a list:

for my $var ( 1..4 ){ ...        # expression using range operator

for my $var ( @array ){ ...      # array

for my $var ( 6, 7, 'A', 'B' ){  # literal list
    print "$var  ";
}

# if a variable is not specified, $_ is used by default

for ( 6, 7, 'A', 'B' ){
    print "$_  ";
}
[download]