Beefy Boxes and Bandwidth Generously Provided by pair Networks
go ahead... be a heretic
 
PerlMonks  

comment on

( #3333=superdoc: print w/replies, xml ) Need Help??
Arguments are passed "by reference" in perl subs, allowing in-place modification. So, you can do things like the following:
sub double_it { $_[0] *= 2 } my $x = 1; print "\$x is $x\n"; double_it($x); print "\$x is now $x\n";
and have
$x is 1 $x is now 2
When you use:
my ($url, @list) = @_;
you're creating copies of the input arguments, so when you modify them you don't have any side-effect outside the function. In your code, these copies are inefficient and not needed, because the code is quite simple and you don't perform in-place modifications. So, you simply grab the first parameter, and use the resulting @_ instead of @list, saving space and time:
sub links { my $url = shift; # This removes the first element of @_ map { "$url/$_" } @_; # You don't need return :) }
I also find this construct useful when porting functions into classes. When you transform a plain function in a class/object method, the first parameter that's passed is the class name/reference to object, so if you have a function:
sub some_func { # ... some stuff? my ($foo, $bar, $baz) = @_; # ... other stuff }
you can transform it at once:
sub some_func { my $self = shift; # Maybe do some checks with $self first? # ... some stuff? my ($foo, $bar, $baz) = @_; # ... other stuff }
in a much cut-and-paste fashion. But do check the code!

Flavio (perl -e "print(scalar(reverse('ti.xittelop@oivalf')))")

Don't fool yourself.

In reply to Re^3: Turning foreach into map? by polettix
in thread Turning foreach into map? by ghenry

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Are you posting in the right place? Check out Where do I post X? to know for sure.
  • Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
    <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>
  • Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
  • Want more info? How to link or How to display code and escape characters are good places to start.
Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others scrutinizing the Monastery: (1)
As of 2023-01-29 05:50 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    No recent polls found

    Notices?