PHP字符串函数nl2br需要注意的小细节

<?php
        /**
         * nl2br
         * **/
        $string1 = "hello i am PHP i am very smart!\n";
        $string2 = 'hello i am PHP i am very smart!\n';
        echo nl2br($string1);//转换双引号字符串
        echo nl2br($string2);//转换单引号字符串
?>

hello i am PHP i am very smart!<br />
hello i am PHP i am very smart!\n