Python:使用相对路径导入Excel文件

我试图导入一个Excel文件，该文件与脚本不在同一文件夹中.我需要在上面找到一个文件夹，然后再放入另一个文件夹(B_folder)，然后有文件2_file.xlsx

I tried to import an excel file which is not within the same folder than the script. I need to get one folder above, then into another folder (B_folder) and there is file 2_file.xlsx

我尝试过:

df = pd.read_excel(r'..\B_folder\2_file.xlsx')

并得到:

FileNotFoundError: [Errno 2] No such file or directory: '..\\B_folder\\2_file.xlsx'

也尝试过:

• 以斜杠代替反斜杠

• foreslash instead of backslash

在路径前没有'r'

但是我总是收到上面或这个错误消息:

but I always get the error message above or this one:

OSError: [Errno 22] Invalid argument: '..\\B_folder\2_file.xlsx'

怎么了?