如何通过相对路径获取“其他”项目文件的绝对路径？

Question

How to obtain absolute path via relative path for 'other' project files, not those python file in the project, like Java?

D:\Workspaces\ABCPythonProject\

|- src
|   |-- com/abc
|       |-- conf.py
|       |-- abcd.py
|       |-- defg.py
|       |-- installation.rst
|- resources
|   |-- a.txt
|   |-- b.txt
|   |-- c.jpg

For example, I would like access 'a.txt' or 'b.txt' in python codes like 'abcd.py' in a simple manner with variable like 'resource/a.txt', just like a Java project in Java.

In short, I want to get ' D:\\Workspaces\\ABCPythonProject\\resources\\a.txt ' by ' resources\\a.txt ', which is extremely easy to do in Java, but is seemingly extremely difficult to achieve in Python.

(If I use the built-in python methods like 'os.filePath.join(os.filePath.dirname(_file__), 'resources/a.txt')', os.path.dirname('resources/a.txt'), os.path.abspath('resources/a.txt'), ..., etc., the results is always " D:\\Workspaces\\ABCPythonProject\\com\\abc\\resources\\a.txt ", a non-exit file path. )

How to achieve this?

Answer 1

You can use those built-in python methods, but if you call your script in ../src/com/abc. Your os.filePath() function will execute in your current directory. Your current directory is your execution directory (directory of Python script!!) At first you should change directory to access your .txt-file, because python does not execute in your "ABCPythonProject" directory. Obviously you can not access to recourses/a.txt this way, because you have to change to directory "ABCPythonProject" to check this path.

os.chdir("D:\Workspaces\ABCPythonProject")

You can check your directory, you are currently in with:

print (os.getcwd())

Answer 2

This sample might benefit from a little cleaning, but it does the job.

import os
k = os.path.abspath(os.path.join(".", os.pardir)) # one level up
print k
k = os.path.abspath(os.path.join(k, os.pardir))   # two levels up
print k
k = os.path.abspath(os.path.join(k, 'resources/a.txt'))   # two levels down
print k  

Starting in directory C:\\Users\\Philip\\AppData\\Local\\Temp\\src\\com output is

C:\Users\Philip\AppData\Local\Temp\src
C:\Users\Philip\AppData\Local\Temp
C:\Users\Philip\AppData\Local\Temp\resources\a.txt