Re^4: Hash assignments using map

Thanks varian. This makes sense.

I want to quickly create a hash with keys that are the elements of the list. All I want access to is the keys...I don't care what the values are. I can then use exists to see if those keys either do or do not exist in another hash.

Thanks again!

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Re^5: Hash assignments using map
by shmem (Chancellor) on Feb 24, 2007 at 20:32 UTC

All I want access to is the keys...

and

my @keys = qw{ a b c d };
my %hash = map { $_,1 } @keys;
[download]

$_="a";$_++; # $_ is b now

$_++

In the loop

my %hash;
foreach ( @keys ) {
    $hash{$_}++;
}
[download]

you are also using two variables - in a shortcut:

you create a new hash slot with key $_
you increment (the previously undefined) value for that key

So, it's the same thing with keys and values here. With map iterating over an array of keys, you must provide a value to have pairs to be stored as (key,value) in a hash.

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

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