my question is pretty much what the title suggests. my research has led me to try something like this:
import os
pathname = os.path.abspath("some/relative/directory")
print pathname
this problem is that whenever i do something like this, it simply returns whatever relative directory i gave it preceded by my python directory. for example:
C:\Python27\some\relative\directory
which is not even an existing directory on my computer. i understand that the python interpreter searches the working directory by default, but what i'd like to do is have it search my entire computer for an absolute path that contains the partial directory i specify.
the purpose of this is for me to create an exe (using py2exe) that can search for an arbitrary directory on any computer. is there a method for doing this in the standard library or through some available module - or would i have to implement the algorithm myself?
abspath is based on getcwd. Most likely, your current working directory simply isn't what you expect.
You can change the code that launches your script, change directories manually, or just use chdir in Python.
Did you try os.path.realpath("my/relative/dir")? Actually it seems the directory may not exist, but if it does, it will resolve symbolic links and whatnot.
Related
Whenever I do a project for computer science, I have to make sure all of my files are located in the same folder, or I'll have errors. If I want to use a file from somewhere else, I have to insert it into the path. I do these things but don't fully understand what is happening or why. Why is the path changed in the runtime environment?
When you run a python script you are executing it in the current working directory /home/user/python.py for example. That means this script since it lives in /home/user has access to everything in that path. However you should be able to access any other directory from here as long as the permissions are setup right. You would do that by using relative paths. so for example /home/user/python.py could access a file that is /home/example/file.txt by giving it the path ../example/file.txt from the python project.
Have you tried adding the path using sys.path.append? If you don't want to do that every time then you can set (Windows) %PYTHONPATH% to include your custom path. That's what I do for my include folder.
I know there must be a really obvious answer, but it eludes me. Where does "/folder1/folder2/file.ext" save to in Python? In some code I thought (incorrectly) that it would save the file to a relative path, but when I checked folder2 it wasn't there. However, it seemed to still take up the hard disk space. I did a search on my hard drive and couldn't find the file. Where did it go? Again, I'm aware that there must be a really obvious answer out there, but I am just learning to code.
Firstly I would read about the os module and the module search path.
I opened the IDLE 3.7.0 on my Windows 10 machine and did the following:
>>> import os
>>> os.getcwd()
'C:\\Python37'
>>> os.path.abspath('./folder1')
'C:\\Python37\\folder1'
Windows expands the . to represent the current working drive, thus wherever the interpreter is looking is where your folders will reside.
In the links, it talks about how sys.path works (in short the directory containing the current script is placed at the front of it [e.g. the current working directory] for searching).
So, in short, either run your script directly from the directory or call os.chdir('/your/desired/path').
I'm new and I have no idea where the default directory for the open() function is.
For example open('whereisthisdirectory.txt','r')
Can someone advise me? I've tried googling it (and looking on stackoverflow) and even putting a random txt file in so many folders but I still can't figure it out. Since I'm beginning, I want to learn immediately rather than type "c:/directory/whatevevr.txt" every time I want to open a file. Thanks!
Ps my python directory has been installed to C:\Python32 and I'm using 3.2
os.getcwd()
Shows the current working directory, that's what open uses for for relative paths.
You can change it with os.chdir.
If you working on Windows OS first type
import os
then type
os.getcwd()
and it should print the current working directory.
The answer is not python-specific. As with programs written in any other language, the default directory is whatever your operating system considers the current working directory. If you start your program from a command prompt window, the CWD will be whatever directory you were in when you ran the program. If you start it from a Windows menu or desktop icon, the CWD is usually defined alongside the program's path when creating the icon, or else falls back to some directory that Windows uses in the absence of that information.
In any case, your program can query the current working directory by calling os.getcwd().
The default location is the CWD (Current Working Directory), so if you have your Python script in c:\directory and run it from there, if you call open() it will attempt to open the file specified in that location.
First, you must import:
import os
Then to print the current working directory:
os.getcwd()
If you want to change the current working directory:
os.chdir('your_complete_required_path')
create the .txt file in the directory where u have kept .py file(CWD) and run the .py file.
The open() function for file always creates files in the current working directory. The best way to find out your current working directory is to find three lines of small code:
import os
current_working_directory = os.getcwd()
print(current_working_directory)
Run this above code and you will get your current working directory where open() function creates a new file. Good Luck!
If you’re running your script through an interpreter (i.e pycharm, VSCode etc) your Python file will be saved, most likely, in my documents (at least in VSCode, in my personal experience) unless you manually save it to a directory of your choosing before you run it. Once it is saved, the interpreter will then use that as you current directory so any saves your Python script will create will also automatically go there unless you state otherwise.
it depends on how you run it from the terminal
like this, it is going to look in your home directory
C:\Users\name>python path\file.py
and like this, it is going to look next to your file
C:\Users\name>cd path
C:\Users\name\path>python file.py
I have a process which is loading a DLL from a place not listed in the documented search order (docs linked below). I want to know why.
Here's the description of my setup:
I have a folder 'c:\foo' containing a.dll and b.dll.
I have a python script also stored in c:\foo.
The python script does a LoadLibrary('c:/foo/a.dll') (via ctypes)
a.dll is linked against the import library for b.dll (ie using implicit linking).
I run the python script with a current directory of, say, c:. It could be anything.
b.dll is loaded from c:\foo, even though that isn't on the search path.
Looking at the process monitor trace, I can see that all the documented search paths were tried first, and all failed. Then the python process tried and failed to open "C:\WINDOWS\assembly\GAC\Microsoft.VC80.CRT.mui\8.0.50727.4053_en-US_1fc8b3b9a1e18e3b\Microsoft.VC80.CRT.mui.DLL", then it opened c:\foo\b.dll.
So, it seems to be that the a.dll's directory is being searched for b.dll even though the docs don't say it should be. Also, this happens after looking on the system path, which is mad. Can anyone shed any light on this?
The same thing happens with a MatLab script that also uses a.dll.
I'm running Windows XP SP 3.
This MSDN article explains the default search order. I quote:
The directory specified by lpFileName.
The system directory. Use the GetSystemDirectory function to get the path of this directory.
The 16-bit system directory. There is no function that obtains the path of this directory, but it is searched.
The Windows directory. Use the GetWindowsDirectory function to get the path of this directory.
The current directory.
The directories that are listed in the PATH environment variable. Note that this does not include the per-application path specified by the App Paths registry key. The App Paths key is not used when computing the DLL search path.
a.dll is probably using runtime dynamic linking as a last resort
http://msdn.microsoft.com/en-us/library/ms686944%28VS.85%29.aspx
I am using Python 2.5 on CentOS 5.5
I have got a file called MultipartPostHandler.py, I am supposed to use it like this:
import MultipartPostHandler
But I dont know where should I put the file MultipartPostHandler.py so I can use it. Thanks a lot!
http://docs.python.org/tutorial/modules.html#the-module-search-path
When a module named spam is imported,
the interpreter searches for a file
named spam.py in the current
directory, and then in the list of
directories specified by the
environment variable PYTHONPATH. This
has the same syntax as the shell
variable PATH, that is, a list of
directory names. When PYTHONPATH is
not set, or when the file is not found
there, the search continues in an
installation-dependent default path;
on Unix, this is usually
.:/usr/local/lib/python.
Actually, modules are searched in the
list of directories given by the
variable sys.path which is initialized
from the directory containing the
input script (or the current
directory), PYTHONPATH and the
installation- dependent default. This
allows Python programs that know what
they’re doing to modify or replace the
module search path.
So, you have to put it into the current directory or use sys.path to show your program where the searched module is.
The easiest is to put it in the same folder as the code you're writing.
If you got it from somebody who provides an installer, then to be safe, just run the installer.
If it's just something you grabbed specifically for this project, put it in the same folder as the .py files that you're writing.
Otherwise (if you're planning to use it for a few projects and don't want to copy/paste the file), the safest place to put it is probably in the /lib/site-packages sub-directory of the directory where Python is installed.
The easiest - yes, is to put it in the same directory where you have the importer python code. Also, you can export PYTHONPATH environment variable which points to the directory (or directories separated by :) where you have MultipartPostHandler.py. Another option: make it distributable. This will be useful if you are going to publish your code.