如何从字符串中删除精确出现的字符？

例如，我有一个像这样的字符串：

string str = "santhosh,phani,ravi,phani123,praveen,sathish,prakash";

我想删除字符,phani from str.

现在，我正在使用str = str.Replace(",phani", string.Empty);

那么我的输出是：str="santhosh,ravi123,praveen,sathish,prakash";

但我想要一个像这样的输出：str="santhosh,ravi,phani123,praveen,sathish,prakash";

string str = "santhosh,phani,ravi,phani123,praveen,sathish,prakash";
var words = str.Split(',');
str = String.Join(",", words.Where(word => word != "phani"));