Python：如何将 go 一个文件夹返回到 pathlib

Question

After watching my work folder get cluttered I have moved code files corresponding together into a subfolder. The problem is that the data my program uses is itself placed in a subfolder of the now parent folder. I used pathlib to extract the data from the subdirectories like so:

DATA_DIR = pathlib.Path.cwd().joinpath("Kokam NMC 46 Ah EET","CheckUps",
                                       "Calend_ID{id_nr}_{temp}_{SoC}".format(id_nr = id_nr, temp = temp, SoC = SoC ))

where Kokam NMC 46 Ah EET is the parent folder to CheckUps and so on. Now what I need is to adjust this command in such a way that the path goes back into the parent folder and then into Kokam NMC 46 Ah EET etc. I had done some research on this site and tried what seemed like a solution in some cases, namely to add ".."

DATA_DIR = pathlib.Path.cwd().joinpath("..","Kokam NMC 46 Ah EET","CheckUps",
                                       "Calend_ID{id_nr}_{temp}_{SoC}".format(id_nr = id_nr, temp = temp, SoC = SoC ))

which did not work. Similarly I tried the same strategy for saving a plot

plt.savefig('../Graphs/Impedanz Plot von ID{id_nr} NMC{nmc_nr} bei {x} Hertz'.format(id_nr = id_nr, temp = temp, SoC = SoC, nmc_nr = nmc_nr, x=hertz),
                bbox_inches = 'tight', dpi = 600)

which returned

FileNotFoundError: [Errno 2] No such file or directory: '../Graphs/Impedanz von ID01 NMC46 (bei 35C und 100SOC).png'

How does one adjust for backtracking into parent folders using pathlib ? And if pathlib does not have this feature is there another way to do it?

Thank you!

Answer 1

Instead of .. , do path.parent :

>>> pathlib.Path.cwd()
PosixPath('/home/jan/Downloads')

>>> pathlib.Path.cwd().parent
PosixPath('/home/jan')

For your second attempt, make Python calculate an absolute path from a relative one.

>>> os.path.abspath('../')
'/home/jan'

Also make sure the path you are trying to save to is the actually correct path by printing it.