That's not how delete works in this context. Try $_[2]="changed!";
On Thu, Dec 19, 2019, 4:34 PM Morse, Richard E.,MGH via Boston-pm < [email protected]> wrote: > I think the issue is that you aren’t passing the array to the subroutine, > you’re passing a new flattened list of aliases to the elements of the > array. > > If you modify a parameter (`$_[3] = ‘xyzzy’;), it changes at the top > level, > but that’s because you’re modifying the aliases parameter. > > From `perlsub`: > > > The array @_ is a local array, but its elements are aliases for the > > actual scalar parameters. > > So, you create an array “@list”, which has a bunch of elements. You pass > that array to the killer functions, but Perl flattens the array, and > instead of passing “@list”, it passes @_ = ( $list[0], $list[1], > $list[2], > $list[3], …). When you modify @_, you’re not modifying @list, just @_. If > you change $_[2], you change the aliases item, which changes the value > that > $list[2] points to, so you can change it that way, but you can’t change > @list itself. > > If you need to modify @list, you need to pass the sub a reference to > @list > — `killer(\@list)` — similar to why you had to escape @list to pass it to > `Dumper`. You would then be able to delete an item with > `delete($_[0]->[2])`. > > HTH, > Ricky > > On Dec 19, 2019, at 3:53 PM, Greg London <[email protected]> wrote: > > > External Email - Use Caution > > > > use Data::Dumper; > > > > sub killer{ > > delete($_[2]); > > } > > > > my @list = qw( alpha bravo charlie delta echo fox); > > print Dumper \@list; > > killer(@list); > > print Dumper \@list; > > > > > > I would expect the second Dumper statement to show one less element. > > Greg > > > > _______________________________________________ > > Boston-pm mailing list > > [email protected] > > https://mail.pm.org/mailman/listinfo/boston-pm > > _______________________________________________ > Boston-pm mailing list > [email protected] > https://mail.pm.org/mailman/listinfo/boston-pm > _______________________________________________ Boston-pm mailing list [email protected] https://mail.pm.org/mailman/listinfo/boston-pm
