Vaishnavi Saba wrote:
Hi,
Hello,
My query: In the code shown below, How does *grep* compare a scalar( *
$seen{$_}* ) with an array of hash references ( *...@_* ).
An array in scalar context returns the number of elements in the array
and @_ (which is an alias to @common) contains 3 elements so:
return grep { $seen{$_} == @_ } keys %seen;
is the same as:
return grep { $seen{$_} == 3 } keys %seen;
and in list context grep returns a list of all the keys of %seen where
the value of that key is 3 and in scalar context grep returns a count of
the number of keys that match.
=====
@common = inter( \%foo, \%bar, \%joe );
sub inter {
my %seen;
for my $href (@_) {
while (my $k = each %$href ) {
$seen{$k}++;
}
}
return grep { $seen{$_} == @_ } keys %seen;
}
========
When I try printing the @_, I get the output as "HASH(0x40030354)
HASH(0x400303d8) HASH(0x40037e98)".
That is because @_ (which is an alias to @common) contains three hash
references.
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
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