Since foo() returns a list, why not assign it to a list:

my @bar=foo();
print "@bar\n";
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To get the number of keys returned by foo(), it'd be:

my $baz=scalar(@bar);
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(Update: the "wantarray" answers are probably better, I'm a young grasshopper learning, blah blah blah. :o)

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Me spell chucker work grate. Need grandma chicken.