ikegami's solution is simple and elegant, as well as being what I would probably use. But, for the sake of TIMTOWTDI, and to introduce a very handy module, let me suggest: 

use List::MoreUtils qw(zip);
my @orig = qw(1 33 45 66);
my @doubled = zip @orig, @orig;
print "@doubled\n";

[download]


TGI says moo

In reply to Re: How do I double up elements within an array? by TGI
in thread How do I double up elements within an array? by Anonymous Monk

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