On Jul 19, Robert Citek said:
On Jul 19, 2005, at 5:19 PM, Wiggins d'Anconia wrote:
Close. You want a hash slice.
@[EMAIL PROTECTED] = @vals;
A marvelously Perlish construct.
http://danconia.org
Sweeeeet! Thanks a bunch.
Do you have a good reference which explains this? I've looked in both the
Camel and Llama books, but didn't see the @$ construct anywhere.
Well, let's take a step back. You don't have a *hash*, per se, you have a
reference to a hash.
$hash->{x} = $y;
implies (rightly so) that $hash is a reference to a hash. If you had a
hash without the reference, you would have written
$hash{x} = $y;
So let's deal with that for the moment. Slices are ways to access a list
of values at one time (whether for reading or assigning). Here are single
array and hash accesses:
$array[3] = 10;
$hash{name} = 'japhy';
and here are array and hash slices:
@array[3,5,7] = (10, 15, 20);
# same as ($array[3], $array[5], $array[7]) = (10, 15, 20)
@hash{'name', 'state'} = ('japhy', 'NJ');
# same as ($hash{name}, $hash{state}) = ('japhy', 'NJ')
You can use slices on the right-hand side of an = as well:
@pair = @array[0..1];
@contact = @hash{'phone', 'email'};
So now. What's the @$hash{...} syntax? Well, like I said, you don't have
just a hash, you have a hash reference. In the place of the *name* of the
hash in '$HASHNAME{...}' and '@HASHNAME{...}', you can put a reference;
thus: '$$hashref{...}' and '@$hashref{...}'.
The first one, $$hashref{...}, is more commonly written as you wrote it:
$hashref->{...}. But for the second one, there is no -> syntax that
works. You just have to use @$hashref{...}.
For more, please read
perldoc perldata
to learn about slices, and
perldoc perlreftut
to be introduced to references. Further reading is:
perldoc perlref
perldoc perllol
perldoc perldsc
--
Jeff "japhy" Pinyan % How can we ever be the sold short or
RPI Acacia Brother #734 % the cheated, we who for every service
http://japhy.perlmonk.org/ % have long ago been overpaid?
http://www.perlmonks.org/ % -- Meister Eckhart
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