StringBuilder与string的Replace方法的区别

StringBuilder的Replace方法会更改对象本身的值，例StringBuilder s1="1234";s1.Replace("4","5");s1的值为"1235";

string的Replace方法不会更改对象本身的值，例string s1="1234";string s2=s1.Replace("4","5");s1的值仍然为"1234";s2的值为"1235";