Assuming I've not misintepreted your question, I'd lean towards a solution something like this: 
my @defaults = qw/one two three four five/;
my @a = qw/un deux trois/;

$a[$_] ||= $defaults[$_] for (0 .. $#defaults);

print "@a\n";
# prints "un deux trois four five"

[download]
Again, if you're looking for a completely either-or approach to the two lists, then the aforementioned trinary operator is probably the best choice. If you want to take from @a or @defaults on a per-element basis, then the trinary operator won't give you the desired results -- you'll need to use an approach like mine or RMGir's above.

blokhead

In reply to Re: default values for lists by blokhead
in thread default values for lists by pike

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.