On 14/08/2011 23:19, Rajeev Prasad wrote:
in this simple example. i am not able to figure what is the bitwise
funtion doing:
my @subArray = grep { $_& 1 } @array;
The & operator requires the types of its operands to be identical -
either string or numeric. In either case the values are ANDed together
to produce a value of the same type.
what is the significance of 1 here?
It is a numeric value with just bit zero set. It is ANDed with the value
in $_ so that if $_ holds an odd or even number the result will be 1 or 0.
is this equivalent? { 1& $_ }
Yes.
does the EXPR inside grep's curly braces have to produce the grepped
text or just a true false value? i thought like in regular shell it
produces whatever it grepped.
The result of the Perl grep operator is a list where the expression is
true. In this case, @subArray becomes a copy of the odd elements of
@array (those that, when ANDed with 1 are non-zero).
HTH,
Rob
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