You're probably thinking of ||

If you replace && with || in the code, || would short-circuit on $y and $z, but not on $x.

Short-circuiting basically means to stop evaluating a logical expression once its outcome is known. For logical And, that means stop evaluating once the first false value is seen, for logical Or, stop once the first true value is seen.

Short-circuit behavior, especially Perl's behavior of returning the last evaluated value, can be useful for:

  1. efficiency, e.g. if (complex_operation() && other_complex_operation()) { ... } doesn't call other_complex_operation() if complex_operation() is false
  2. combining statements, e.g. $_%3 && print "$_%3 is true" for 0..10 (though readability can suffer that way), or open(...) or die $!;
  3. setting a variable to one value or another, e.g. my $option = $user_option||"default value";

In reply to Re^2: Kindly let me know what exactly && does in Perl by Anonymous Monk
in thread Kindly let me know what exactly && does in Perl by pritesh

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!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • 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, details, 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, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            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.