Re: Perl - pass by reference v pass by value

On Tue, 21 Sep 2021 09:09:46 +0000, Paul Webster
<Paul.Webster.a8bjuo-NUepA2SMhDQqspMVqqL2D+4xXEVPTSb/[email protected]> wrote:

> I did not expect that the values in $variable1 to change through me
> changing a new local variable $newvalue.

That is because my is not necessarily introducing a local variable. When
used in an iteration

   foreach my $var ( $x ) {
       # $var is an alias to $x

$var becomes an _alias_ to the value referenced. If you modify it, you
modify the original. 

If you don't want that, the correct syntax is

    foreach ( ... ) {
        my $var = $_;           # now the value is copied

HTH,
	Johan