A hash slice in a scalar context returns the last element. @x{1, 2} equals (2, undef) and so undef is used as the boolean.

The second one constructs a new array, and therefore the array count is returned in a scalar context, 2.

%x = (1 => 2);

print '@x{1, 2} in scalar equals: \'' . (scalar @x{1, 2}) . "'\n";
# Returns ''

print '@{[@x{1, 2}]} in scalar equals: \'' . (scalar @{[@x{1, 2}]})) .
+ "'\n";
# Returns 2

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In reply to Re: nonempty false list by wind
in thread nonempty false list by Anonymous Monk

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