in reply to Re: Unique values in array
in thread Unique values in array

Thank you, it now works. If possible can you please explain what is going on in this statement? 
print map "$_\n", keys %{ {map {$_ => 1} @array} };

[download]
I am lost on the keys and map part??

Replies are listed 'Best First'.
Re: Re: Re: Unique values in array
by broquaint (Abbot) on Jun 27, 2003 at 15:21 UTC
    Alrighty, let's break it down then 
    map { $_ => 1 } @array

    [download]
    For each value in @array apply the transform in the block (denoted by the curly braces), in this case create a two element list consisting of each element of the list and a literal 1, collect the output of those transforms and return them as a list. So the map creates a list of key-value pairs (although the value is superfluous in this case) perfect for a hash ... 
    { map { $_ => 1 } @array }

    [download]
    The extra curly braces around the map statement create an anonymous hash, so all duplicate keys in the list created by map are collapsed in the anonymous hash. 
    keys %{ {map {$_ => 1} @array} }

    [download]
    Dereference the anonymous hash created and return a list of its keys. 
    print map "$_\n", keys %{ {map {$_ => 1} @array} };

    [download]
    The final map then simply a creates a list where each key has a \n appended and then print prints that list.
    HTH

    _________
    broquaint

[reply]
[d/l]
[select]
      Thank you for all the explanations!
[reply]

In Section Seekers of Perl Wisdom