将Python代码转换为PHP

我不知道在野外有任何Python到PHP的转换器，但是移植它应该是一件轻而易举的事，相似之处很容易发现：

function calcNumEntropyBits($s) {        if (strlen($s) <= 0) return 0.0;        $symCount = array();        foreach (str_split($s) as $c) {     if (!in_array($c,$symCount)) $symCount[$c] = 1;     else $symCount[$c] ++;        }        $entropy = 0.0;        foreach ($symCount as $c=>$n) {     $prob = $n / (float)strlen($s);     $entropy += $prob * log($prob)/log(2);        }        if ($entropy >= 0.0) return 0.0;        else return -($entropy*strlen($s));}function testEntropy($s):        printf("Bits of entropy in '%s' is %.2f",$s,calcNumEntropyBits($s));testEntropy('hello world');testEntropy('bubba dubba');testEntropy('aaaaaaaaaaa');testEntropy('aaaaabaaaaa');testEntropy('abcdefghijk');

第一个函数的最后几行也可以写成标准的PHP三元表达式：

return ($entropy >= 0.0)? 0.0: -($entropy*strlen($s));