if (strpos($str, '.') !== FALSE)
{
 echo 'Found it';
}
else
{
 echo 'Not found.';
}

请注意，您需要与!==运算符进行比较.如果使用!=或<>并且'.'在位置0上找到，嘿！ 0比较等于FALSE，您输了.这样一来，您就可以在周末将生产网站指向开发数据库，​​而在星期一返回时就不会感到无穷无尽.

Note that you need to compare with the !== operator. If you use != or <> and the '.' is found at position 0, hey! 0 compares equal to FALSE and you lose. This will cause you to point a production website at a development database over the weekend, causing no end of joy when you return monday.