问题是您对replace的结果没有执行任何操作.在Python中，字符串是不可变的，因此任何处理字符串的操作都将返回新字符串，而不是修改原始字符串.

The problem is you're not doing anything with the result of replace. In Python strings are immutable so anything that manipulates a string returns a new string instead of modifying the original string.

line[8] = line[8].replace(letter, "")