thanks once again to everybody.

I asked the question as it was not clear for me why comparing 0 to a non-empty string returns true. The other fact I came along during my test for this issue was that undef == 0 also returns true.

After our discussion and bit more thinking my understanding changed to: the string or undef doesn't represent any (other) number so the '==' operator treats this as '0'. The only other possibility would be always return false in case one or both options are not numeric. Current behavior is surprising for me but maybe it has also some advantages.

Perhaps a perl guru spend some seconds talking about it if he comes here...


In reply to Re^2: confused: string and number comparison by wwe
in thread confused: string and number comparison by wwe

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.