Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??

I agree that a documentation patch is the best response. Since the value for a key can be literally any scalar, it is impossible to think of a return value that would serve to distinguish between the two cases (at least without some perl magic).

We can imagine delete returning a hash or a list of key-value pairs, but (besides breaking compatibility) that would injure idioms that are more useful than knowledge of which keys existed before a deletion. The idiom for re-keying a value, $foo{'bar'} = delete $foo{'baz'}; would be wrecked, for instance.

A workaround can be devised pretty easily if we need the existence information, my @actual_values = delete @a{ grep { exists $a{$_}} @somekeys};
There are lots of variations possible on that snippet.

After Compline,
Zaxo


In reply to Re: Deleting undef values from a hash by Zaxo
in thread Deleting undef values from a hash by liz

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 contemplating the Monastery: (4)
    As of 2014-09-21 15:28 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      How do you remember the number of days in each month?











      Results (172 votes), past polls