PHP将“0”视为空？

Question

I have encounteed an issue with php treating "0" differently.

I run following script on 2 different machines:

$a = "0";
if ($a) {
    echo("helo");
}

1) Local Machine -> PHP 5.2.17 -> it treated "0" as valid and print the 'helo'

2) Server -> PHP 5.3.6 -> it treated "0" as empty/false and won't print the 'helo'

Is this due to the php configuration (if yes, what configuration) or php version?

Answer 1

That's how it is supposed to. PHP interprets strings in boolean context. The "0" there is equivalent to an actual 0. (See also http://www.php.net/manual/en/types.comparisons.php)

What you meant to test for is probably:

if (strlen($a)) {