Beefy Boxes and Bandwidth Generously Provided by pair Networks DiBona
Perl-Sensitive Sunglasses
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
I'm working through Hall and Schwartz's Effective Perl Programming: Writing Better Programs with Perl and had a small question about the passage below:
To a certain extent, idiom and style overlap. Some idioms, like print sort <>, are inarguable, but there are certainly gray areas:
foreach $key (sort keys %h) { print "$key: $h{$key}\n"; }
Print key-value pairs from %h one per line.
print map "$_: $h{$_}\n", sort keys %h;
Another way to print key-value pairs. The first example above is very plain Perl. It is efficient and readable and uses only basic features of the language. The second example is shorter and, some might argue, has a higher "cool factor" because it uses the nifty map operator and a list context in place of the mundane foreach loop in the first. However, you should consider yourself and your potential audience before leaving code like the second example for posterity, because it is definitely more obscure (but not that obscure) and might even be less efficient.
In my reading on perlmonks I've definitely noticed a bias towards the use of map and grep functions, and so I've been taking strides towards becoming more comfortable implementing them in my code (basic as it may be). Even so, I would like to understand in what ways the map version of the code above would be less efficient than the more verbose foreach loop? Is efficiency being sacrificed for the versatility/style of map? Is there a difference in efficiency at all? I assumed the two methods above to be interchangeable, but should I be being more selective of the situations where I use map?
The above segment is taken from Effective Perl Programming: Writing Better Programs with Perl By Joseph N. Hall, Randal L. Schwartz Publisher : Addison Wesley Pub Date : December 30, 1997 ISBN : 0-201-41975-0 and in no way my own.

In reply to Efficiency of map vs. more verbose basic/fundamental code by marquezc329

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



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • Outside of code tags, you may need to use entities for some characters:
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

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

    How do I use this? | Other CB clients
    Other Users?
    Others studying the Monastery: (14)
    As of 2014-04-24 11:07 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      April first is:







      Results (565 votes), past polls