How do I pass in several lists to a sub in Perl and avoid the contents of them all getting lumped together?

In Perl,  you call subs with a list as their parameter - so if you simply provide a number of comma separated lists in the call then they'll all get combined into a single list ... not what you want much of the time.

The solution is to use the \ operator to pass the ADDRESS of each list into the sub; it makes the internal code in the sub slightly more complex, but it cures the problem.

Example:
Code:

#!/usr/bin/perl #%% Passing several lists into a sub # Passing several lists to a Perl sub @breakfast = qw(sausage bacon eggs); @lunch = qw(kurma, nan, rice, dhansak); @teatime = qw(water rest); # WRONG - The lists get combined into one list # Then there's no way of keeping them apart within printmen1 (@breakfast,@lunch,@teatime,("pizza","McDonalds")); sub printmen1 {        print "FIRST call - one long list\n";        @igot = @_;        print $#igot," @igot\n";        } # RIGHT - Passing references to lists # Then they're separated internally printmen2 (\@breakfast,\@lunch,\@teatime,["pizza","McDonalds"]); sub printmen2 {        print "SECOND call - a list of lists\n";        @igot = @_;        for ($k=0; $k<@igot; $k++) {                @current = @{$igot[$k]};                print "$k:... @current\n";        } }

Runs:

Code:

[localhost:~/marpl] graham% perl 2lp FIRST call - one long list 10 sausage bacon eggs kurma, nan, rice, dhansak water rest pizza McDonalds SECOND call - a list of lists 0:... sausage bacon eggs 1:... kurma, nan, rice, dhansak 2:... water rest 3:... pizza McDonalds [localhost:~/marpl] graham%

Note too how I've used square rather than round brackets to pass in the address of anonymous list(s) ...

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