On 03/09/2014 05:00 AM, Shlomi Fish wrote:
Hi Alex,
On Sun, 9 Mar 2014 16:40:54 +1100
Alex Chiang <s3442...@student.rmit.edu.au> wrote:
Hi all,
I'm a perl beginner, and when I tries to practice delete built-in, I find
it's not working as I supposed to.
44 my %employ_list = ("e10220" => "Du", "e10250" => "Vic");
45 # iterate thru with each
46 while ( my ($k, $v) = each %employ_list ) {
47 print " before: key:$k => value:$v \n";
48 if ($k eq "e10220") { delete $employ_list{$k}; }
In addition to what Uri said, you should not delete a key out of a hash (or
add keys) while iterating over it using each(), because this may confuse Perl:
http://perl-begin.org/tutorials/bad-elements/#modifying_iterated_array
that is wrong for delete on the most recent key returned from each (from
perldoc -f each):
If you add or delete
a hash's elements while iterating over it, entries may be
skipped or duplicated--so don't do that. Exception: It is
always safe to delete the item most recently returned by
"each()", so the following code works properly:
while (($key, $value) = each %hash) {
print $key, "\n";
delete $hash{$key}; # This is safe
}
that is what was being done in the OP's code.
uri
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