(BTW, the undef values are correct and to be expected...

I'm not sure how you reach that conclusion? When you assign an even sized list to a hash, every other value starting with the first is a key, and the next is the value assigned to that key.

perl -e"%h = (1=>2, 2=>4, 5=>6, 7=>8, 9=>10); $,='-'; print %h;"
1-2-7-8-9-10-2-4-5-6
[download]

If the keys are all the same, then then hash should end up with a single key, with the value of the last item in the list.

perl -e"%h = (1=>2, 1=>4, 1=>6, 1=>8, 1=>10); $,='-'; print %h;"
1-10
[download]

As you can see, I've eliminated both the join and the X from the equation, but still...

P:\test>perl -e"$,='-'; print %h = (1,1,1,1,1,1,1,1,1,1);"
1-1-1--1-1-1--1-1
[download]

If I do

perl -e"$s = 'fred'; print $s;"
fred

perl -e"print $s = 'fred';"
fred

perl -e"$,='-'; @a=(1,1,1,1,1,1,1,1,1,1); print @a;"
1-1-1-1-1-1-1-1-1-1

perl -e"$,='-'; print @a=(1,1,1,1,1,1,1,1,1,1);"
1-1-1-1-1-1-1-1-1-1
[download]

It doesn't matter whether I assign then print or print the assignment, the results are the same. With a hash the results are different.

The real kicker is that after the print assignment, the hash ends up correct.

perl -MData::Dumper -le"$,='-'; print %h = (1,1,1,1,1,1,1,1,1,1); prin
+t Dumper \%h;"
1-1-1--1-1-1--1-1
$VAR1 = {
          '1' => 1
        };
[download]

It's only the results of printing the assignment that is in error...at least that I've so far discovered.

---

Examine what is said, not who speaks.

"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
Hooray!