note 47409 deleted from language.types.boolean by bobby

Note Submitter: x123 (at) bestof (dash) inter (dot) net ---- another correction to the preceding "correction": "as the documention states" is right, "any non-empty string is true" is wrong : (bool) "0" === false ! (but "00" and "0.0" etc. are true!) So watch out, you can NOT test for non-empty strings using e.g. <?php if (is_string($s)) if ($s) echo " '$s' is a non-empty string"; else echo " '$s' is an empty string"; // wrong for $s='0' ! else echo " $s is not a string "; ?> indeed, for $s='0' this would print: " '0' is an empty string" which is wrong, of course. This is particularly "dangerous" in connection with MySQL which prints FALSE by default as 0, which comes back from a FORM POST as string '0', while PHP prints FALSE as empty string (!); a similar problem is to preserve a NULL value through a FORM post....