//替换指定串
s = string.gsub("Lua is good", "good", "bad") 
print(s)   --> Lua is bad//替换特殊字符
a = "我们使用$";
b =  string.gsub(a, "%$", "RMB");
print(b) --> 我们使用RMB//替换反斜杠
path = a/b/c\d/e.txt
path= string.gsub(path, "\\", "/")
print(path) --> a/b/c/d/e.txt

其他替换参考：

lua 字符串 正则表达式 转义 特殊字符_lua字符串符号转义_GoRustNeverStop的博客-CSDN博客