Suppose you have this code: 
my %hash = (
 a => 1,
 b => 2,
 c => 3,
 d => 4
);

sub foo
{
  my $n = ($_[0]) ? $_[0] : keys %hash;
  return (keys %hash)[0 .. ($n - 1)]; # return %hash keys from 0 to $n
+ - 1
}

my $bar = &foo(); # want to return the number of keys of %hash
print "$bar\n";

[download]
You'll notice that the value printed isn't the num of keys but a key itself. (Suppose the code from the beginning to end of foo function is located in an external package!!) But foo return a list; the value returned by foo is evaluated in an array context and so 'Why does not it work?'

In reply to List context or not? by sguazt

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