Beefy Boxes and Bandwidth Generously Provided by pair Networks
Perl Monk, Perl Meditation
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
keys(%{{reverse %hash}}) <= 1
From the inside out:
  • %hash in list context returns a list of key,value,key,value
  • reverse LIST in list context reverses the list
  • { LIST } returns a ref to an anonymous hash with the given list of keys and values
  • %{ HASHREF } gets the hash given the reference
  • keys %HASH in scalar context returns a count of the keys
Because the anonymous hash is built with keys as the values of the original hash and values as the keys of the original hash, and identical later keys supercede earlier keys, it will have only one key for each unique value from the original hash. So if it ends up with 1 key all the values of the original hash were equal (and if it ends up with 0 keys, the original hash was empty, which may or may not count as having all values equal).

In reply to Re: scanning hash by ysth
in thread scanning hash by hotshot

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 rifling through the Monastery: (14)
    As of 2014-12-26 21:31 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      Is guessing a good strategy for surviving in the IT business?





      Results (176 votes), past polls