How to resolve relative paths in python? - python

I have Directory structure like this
projectfolder/fold1/fold2/fold3/script.py
now I'm giving script.py a path as commandline argument of a file which is there in
fold1/fold_temp/myfile.txt
So basically I want to be able to give path in this way
../../fold_temp/myfile.txt
>>python somepath/pythonfile.py -input ../../fold_temp/myfile.txt
Here problem is that I might be given full path or relative path so I should be able to decide and based on that I should be able to create absolute path.
I already have knowledge of functions related to path.
Question 1
Question 2
Reference questions are giving partial answer but I don't know how to build full path using the functions provided in them.

try os.path.abspath, it should do what you want ;)
Basically it converts any given path to an absolute path you can work with, so you do not need to distinguish between relative and absolute paths, just normalize any of them with this function.
Example:
from os.path import abspath
filename = abspath('../../fold_temp/myfile.txt')
print(filename)
It will output the absolute path to your file.
EDIT:
If you are using Python 3.4 or newer you may also use the resolve() method of pathlib.Path. Be aware that this will return a Path object and not a string. If you need a string you can still use str() to convert it to a string.
Example:
from pathlib import Path
filename = Path('../../fold_temp/myfile.txt').resolve()
print(filename)

A practical example:
sys.argv[0] gives you the name of the current script
os.path.dirname() gives you the relative directory name
thus, the next line, gives you the absolute working directory of the current executing file.
cwd = os.path.abspath(os.path.dirname(sys.argv[0]))
Personally, I always use this instead of os.getcwd() since it gives me the script absolute path, independently of the directory from where the script was called.

For Python3, you can use pathlib's resolve functionality to resolve symlinks and .. components.
You need to have a Path object however it is very simple to do convert between str and Path.
I recommend for anyone using Python3 to drop os.path and its messy long function names and stick to pathlib Path objects.

import os
dir = os.path.dirname(__file__)
path = raw_input()
if os.path.isabs(path):
print "input path is absolute"
else:
path = os.path.join(dir, path)
print "absolute path is %s" % path
Use os.path.isabs to judge if input path is absolute or relative, if it is relative, then use os.path.join to convert it to absolute

Related

list of jpeg files in nested subdirectories

I use the following python code to get list of jpg files in nested subdirectories which are in parent directory.
import glob2,os
all_header_files = glob2.glob(os.path.join('Path/to/parent/directory','/**/*.jpg'))
However, I get nothing but when I cd into the parent directory and I use the following python code then I get the list of jpeg files.
import glob2
all_header_files = glob2.glob('./**/*.jpg')
How can I get the result with the absolute path?(first version)
You have an extra slash.
The os.path.join will insert the filepath separators for you, so you should think of it as this to get the correct directory
join('Path/to/parent directory' , '**/*.jpg')
Even more accurately,
parent = os.path.join('Path', 'to', 'parent directory')
os.path.join(parent, '**/*.jpg')
If you are trying to use your Home directory, see os.path.expanduser
In [10]: import os, glob
In [11]: glob.glob(os.path.join('~', 'Downloads', "**/*.sh"))
Out[11]: []
In [12]: glob.glob(os.path.expanduser(os.path.join('~', 'Downloads', "**/*.sh")))
Out[12]:
['/Users/name/Downloads/dir/script.sh']
You should not join with the trailing slash as you'll end up with the root. You can debug by printing out the resulting path before passing it to glob.
Try to change your code like this (note the dot):
import glob2,os
all_header_files = glob2.glob(os.path.join('Path/to/parent directory','./**/*.jpg'))
os.path.join() joins paths in an intelligent way.
os.path.join('Path/to/anything','/**/*.jpg'))
resolves to '/**/*.jpg' since '/**/*.jpg' is any path, ever.
Change the '/**/*.jpg' to '**/*.jpg' and it should work.
In cases like this, I recommend to always try out the result of a certain function within the python command line. At least, this is how I found out the issue here.
The problem with the code you have posted lies in the use of os.path.join.
In the documentation it says for os.path.join(path, *paths):
If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.
In your case, the component /**/*.jpg is an absolute path, as it starts with a /. Consequently your initial input /Path/to/parent directory is being truncated by the call to the join function. (https://docs.python.org/3.5/library/os.path.html#os.path.join)
I have locally tested the joining part with python3 and for me it is the case, that using os.path.join(any_path, "/**/*.pdf") returns the string '/**/*.pdf'.
The fix for this error is:
import glob2,os
all_header_files = glob2.glob(os.path.join('Path/to/parent directory','**/*.jpg'))
This returns the path 'Path/to/parent directory/**/*.jpg'

Add and change relative directory to an existed path (python script)

There is a default path in a function:
def function(directory):
path = ('/a/b/c/d/e/f/g')
newdirectory = (This is the part I am asking)
I call this function:
from xxx import function:
p('../../x/y')
I need to get a new directory 'newdirectory', which is supposed to be 'a/b/c/d/e/x/y', in order to proceed to the next step, but I don't know how to add the relative directory to an absolute directory and generate a new absolute directory
Use os.path.join() to join the two path strings together, and os.path.abspath() to resolve the relative parts into one absolute path.
import os
print os.path.abspath(os.path.join('/a/b/c/d/e/f/g', '../../x/y'))

python abspath returning path twice

I'm trying to get an absolute path of a relative path string with python but it keeps printing the path twice. For example:
self.path = 'Users/abdulahmad/Desktop'
self.actual_path = os.path.abspath(self.path)
print self.actual_path
my console prints
/Users/abdulahmad/Desktop/Users/abdulahmad/Desktop
and if I change the path to:
self.path = 'Desktop'
my console prints:
/Users/abdulahmad/Desktop/Desktop
shouldn't it just print /Users/abdulahmad/Desktop in both cases?
Probably because the current working directory is /Users/abdulahmad/Desktop.
If you write for example path/to/file it means relative to current working directory and relative to /Users/abdulahmad/Desktop it would mean /Users/abdulahmad/Desktop/path/to/file.
If you read the python3 manual it actually shows an implementation of os.abspath(path) as being the same as os.path.normpath(os.path.join(os.getcwd(), path)). This can be used to get a path relative to arbitrarily provided path. (It also shows that you actually basically joins the current working directory and the supplied (relative) path)

Python function translate relative path ../../ into full path

is there a function that translate relative path ../test.txt into a full path?
example:
the full path is:
/Users/paganotti/Documents/Project/simple/work/paga/
the relative path is:
../test.txt
I want build this result:
/Users/paganotti/Documents/Project/simple/work/test.txt
As you can see translate ../ into "work" folder for build entire path.
Is there general function that acomplish this task?
use this:
import os
os.path.abspath('../test.txt')
Documentation
You can use normpath() from the os.path module to get a normalize path from one with ".." and similar constructs:
base = '/Users/paganotti/Documents/Project/simple/work/paga/'
rel = '../test.txt'
print os.path.normpath(os.path.join(base, rel))

Find the current directory and file's directory [duplicate]

This question already has answers here:
How do you properly determine the current script directory?
(16 answers)
How to know/change current directory in Python shell?
(7 answers)
Closed 5 years ago.
How do I determine:
the current directory (where I was in the shell when I ran the Python script), and
where the Python file I am executing is?
To get the full path to the directory a Python file is contained in, write this in that file:
import os
dir_path = os.path.dirname(os.path.realpath(__file__))
(Note that the incantation above won't work if you've already used os.chdir() to change your current working directory, since the value of the __file__ constant is relative to the current working directory and is not changed by an os.chdir() call.)
To get the current working directory use
import os
cwd = os.getcwd()
Documentation references for the modules, constants and functions used above:
The os and os.path modules.
The __file__ constant
os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
os.path.dirname(path) (returns "the directory name of pathname path")
os.getcwd() (returns "a string representing the current working directory")
os.chdir(path) ("change the current working directory to path")
Current working directory: os.getcwd()
And the __file__ attribute can help you find out where the file you are executing is located. This Stack Overflow post explains everything: How do I get the path of the current executed file in Python?
You may find this useful as a reference:
import os
print("Path at terminal when executing this file")
print(os.getcwd() + "\n")
print("This file path, relative to os.getcwd()")
print(__file__ + "\n")
print("This file full path (following symlinks)")
full_path = os.path.realpath(__file__)
print(full_path + "\n")
print("This file directory and name")
path, filename = os.path.split(full_path)
print(path + ' --> ' + filename + "\n")
print("This file directory only")
print(os.path.dirname(full_path))
The pathlib module, introduced in Python 3.4 (PEP 428 — The pathlib module — object-oriented filesystem paths), makes the path-related experience much much better.
pwd
/home/skovorodkin/stack
tree
.
└── scripts
├── 1.py
└── 2.py
In order to get the current working directory, use Path.cwd():
from pathlib import Path
print(Path.cwd()) # /home/skovorodkin/stack
To get an absolute path to your script file, use the Path.resolve() method:
print(Path(__file__).resolve()) # /home/skovorodkin/stack/scripts/1.py
And to get the path of a directory where your script is located, access .parent (it is recommended to call .resolve() before .parent):
print(Path(__file__).resolve().parent) # /home/skovorodkin/stack/scripts
Remember that __file__ is not reliable in some situations: How do I get the path of the current executed file in Python?.
Please note, that Path.cwd(), Path.resolve() and other Path methods return path objects (PosixPath in my case), not strings. In Python 3.4 and 3.5 that caused some pain, because open built-in function could only work with string or bytes objects, and did not support Path objects, so you had to convert Path objects to strings or use the Path.open() method, but the latter option required you to change old code:
File scripts/2.py
from pathlib import Path
p = Path(__file__).resolve()
with p.open() as f: pass
with open(str(p)) as f: pass
with open(p) as f: pass
print('OK')
Output
python3.5 scripts/2.py
Traceback (most recent call last):
File "scripts/2.py", line 11, in <module>
with open(p) as f:
TypeError: invalid file: PosixPath('/home/skovorodkin/stack/scripts/2.py')
As you can see, open(p) does not work with Python 3.5.
PEP 519 — Adding a file system path protocol, implemented in Python 3.6, adds support of PathLike objects to the open function, so now you can pass Path objects to the open function directly:
python3.6 scripts/2.py
OK
To get the current directory full path
>>import os
>>print os.getcwd()
Output: "C :\Users\admin\myfolder"
To get the current directory folder name alone
>>import os
>>str1=os.getcwd()
>>str2=str1.split('\\')
>>n=len(str2)
>>print str2[n-1]
Output: "myfolder"
Pathlib can be used this way to get the directory containing the current script:
import pathlib
filepath = pathlib.Path(__file__).resolve().parent
If you are trying to find the current directory of the file you are currently in:
OS agnostic way:
dirname, filename = os.path.split(os.path.abspath(__file__))
If you're using Python 3.4, there is the brand new higher-level pathlib module which allows you to conveniently call pathlib.Path.cwd() to get a Path object representing your current working directory, along with many other new features.
More info on this new API can be found here.
To get the current directory full path:
os.path.realpath('.')
Answer to #1:
If you want the current directory, do this:
import os
os.getcwd()
If you want just any folder name and you have the path to that folder, do this:
def get_folder_name(folder):
'''
Returns the folder name, given a full folder path
'''
return folder.split(os.sep)[-1]
Answer to #2:
import os
print os.path.abspath(__file__)
I think the most succinct way to find just the name of your current execution context would be:
current_folder_path, current_folder_name = os.path.split(os.getcwd())
If you're searching for the location of the currently executed script, you can use sys.argv[0] to get the full path.
For question 1, use os.getcwd() # Get working directory and os.chdir(r'D:\Steam\steamapps\common') # Set working directory
I recommend using sys.argv[0] for question 2 because sys.argv is immutable and therefore always returns the current file (module object path) and not affected by os.chdir(). Also you can do like this:
import os
this_py_file = os.path.realpath(__file__)
# vvv Below comes your code vvv #
But that snippet and sys.argv[0] will not work or will work weird when compiled by PyInstaller, because magic properties are not set in __main__ level and sys.argv[0] is the way your executable was called (it means that it becomes affected by the working directory).

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