Is there a compact Perl operation to slice alternate elements from an array?

Question

If I have an array myarray in Python, I can use the slice notation

myarray[0::2]

to select only the even-indexed elements. For

Answer 1

If you don't mind using an obscure feature of $| you can do this:

{
    local $|; # don't mess with global $|
    @ar = ( "zero", "one", "two", "three", "four", "five", "six" );
    $| = 0;
    @even = grep --$|, @ar;
    $| = 1;
    @odd = grep --$|, @ar;
    print "even: @even\\n";
    # even: zero two four six
    print "odd: @odd\\n";
    # odd: one three five
}

or, as a 1 liner:

 { local $|=0; @even = grep --$|, @ar; }

Basically, --$| flip flops between a 0 and 1 value (despite the -- which normally decrements a numeric value), so grep sees a "true" value every other time, thus causing it to return every other item starting with the initial value of $|. Note that you must start with 0 or 1, not some arbitrary index.