open file in 'w' mode: IOError: [Errno 2] No such file or directory

problem ：

When I try to open a file in write mode with the following code: When I try to use the following code to write in When opening a file in mode ：

packetFile = open("%s/%s/%s/%s.mol2" % ("dir", "dir2", "dir3", "some_file"), "w")

Gives me the following error: Gave me the following error ：

IOError: [Errno 2] No such file or directory: 'dir/dir2/dir3/some_file.mol2'

The w mode should create the file if it doesn't exist, right? If the file doesn't exist , w The schema should create a file , Am I right? ？So how can this error ever occur? So how did this error happen ？

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Solution ：

Reference resources ： https://stackoom.com/en/question/A4lw