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Hash of Array slices?

I have a hash of Array as follows:

keys = var1 var2 var3
---------------------
1 a john
2 b kim
3 c tim

such that

$value_ref = $hash{'var1'};
@values = @$value_ref;
print "Values: @values \n";

prints 1 2 3

What I'm trying to figure out is how to get a different hash, ( a simple hash - not a hash of arrays)
which has the same keys and just the values for the second row. I want to end up with

$hash{'var1'} = 2;
$hash{'var2'} = 'b';
$hash{'var3'} = 'kim';

That is, I'd like to take a slice of the original hash, if there is such a thing?
Obviously, what I've done would work if I assigned a different name to $hash. But this isn't really what I'm
looking for. Thus, what I am looking for is the syntax which will let me do this simply and efficiently.

-G

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ozo

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gmanpert

ASKER

I guess still don't understand how your code works?

Using the following code on my hash,

foreach $k (sort keys %hash) {
print "Skey: $k Value @{$hash{$k}} \n";
}

prints,
Skey: var1 Value 1 2 3
Skey: var2 Value a b c
Skey: var3 Value john kim tim

Doing,

$_ = $_->[1] for values %hash;
print ".. $_ \n";

Gets me,

Use of uninitialized value in concatenation ...

Trying,

@$_ = @{$_}[1] for values %hash;
print "... @$_ \n";

Gets me the same thing.

I think what I want is something such as:

foreach $k (sort keys %hash) {
$newhash{$k} = $hash{$k}[1];
}

But, this doesn't seem to work either.

-G

SOLUTION

ozo

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gmanpert

ASKER

Ok, I've gotten a couple of these forms to work but need more help understanding what is actually going on.

$_ = $_ ->[1] for values %hash;

Does what I was after, namely returns a hash with one row of values matched to each key.

Here is what I think I understand... borken into pieces:

@hash_values = values %hash # puts values of hash (array references) into array
for values %hash # sets up loop of those values passing them to $_ each time through
# thus $_ is the reference to the array of values associated with the key
$_->[1] # dereferences the second value of the array and assigns it to $_

My question is how does it get reassigned back to the original hash? It seems to me I should be ending
up with one scalar at the end... but obviously, I don't ?

I could not get this form to work:

@$_ = @{$_}[1] for values %hash;
foreach $k (sort keys %hash) {
print "Skey: $k Value @{$hash{$k}} \n";
}

It runs. But it prints with no values:

Skey: var1 Value
Skey: var2 Value
Skey: var3 Value

Which, brings me to trying to figuring out this form:

@{$hash{$k}}

So,

{$k} # dereferences the hash key
$hash{$k} # retrieves the value of the hash for the key $k
@{$hash{$k}} # I don't really understand this. dereferencing hash value? Assigning it to an array?

-G

SOLUTION

ozo

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