去掉文件名后缀

local str = "shilin1.plist"
function g_removeFileNameSuffix(str)
    local idx = str:match(".+()%.%w+$") --获取文件后缀
    if idx then 
        str = str:sub(1, idx - 1) 
    end
    return str
end
print(g_removeFileNameSuffix(str))
--输出 shilin1