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As others have said, mostly this is a matter of personal style. Sometimes it can make a difference, though, since shift actually modifies @_.

For example, this code could allow a function to act as a regular sub, or as a method (assuming the first argument will never be a reference unless it's called as a method):

my $self = ref $_[0] ? shift : undef; my($arg1,$arg2,$arg3)=@_;

Similarly, if you have a sub that takes a list as its final argument, shifting off the non-list arguments can make it clearer what you're doing, especially if you pass the list on to any other subs:

sub my_sort { my $sortname = shift; return sort $SORTS{$sortname} @_; }

This can also be useful if you decide to goto another sub, since that sub will see the modified @_ as its argument list.

Finally, as a matter of style, I usually get $self or $class with shift in methods and constructors, since it makes it clearer what the explicit arguments are, as compared to the implicit object reference or class name passed in as the first argument.

Update: Corrections and clarifications from jimt.

In reply to Re: shift vs @_ by sgifford
in thread shift vs @_ by Zadeh

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