Mulander wrote: > If I understood you question properly you want to know why people use > shift in subrutines and how does shift work. > > I will try to make it short: > shift works on lists, it removes the first element of the list
perldoc -q "What is the difference between a list and an array" You can't use shift() on a list, only on an array: $ perl -le'my $x = shift qw(10 11 12 13 14)' Type of arg 1 to shift must be array (not list) at -e line 1, at EOF Execution of -e aborted due to compilation errors. > and returns it as a lvalue The term 'lvalue' has a specific meaning in Perl (and CS) which usually means something that can be assigned to. Functions like substr() and vec() are lvalue subs while shift() is not. $ perl -le'my $x = "abc"; substr( $x, 2 ) = "xyz";' $ perl -le'my @x = qw"a b c"; shift( @x ) = "xyz";' Can't modify shift in scalar assignment at -e line 1, near ""xyz";" Execution of -e aborted due to compilation errors. > > [snip] > > Hope this will clear some things up, you can check also: > perldoc -f shift > perldoc -f unshift > perldoc -f pop > perldoc -f push And also: perldoc -f splice perldoc perlsub John -- use Perl; program fulfillment -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] <http://learn.perl.org/> <http://learn.perl.org/first-response>
