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Python - File Path not found if script run from another directory

I'm trying to run a script that works without issue when I run using in console, but causes issue if I try to run it from another directory (via IPython %run <script.py>)
The issue comes from this line, where it references a folder called "Pickles".
with open('Pickles/'+name+'_'+date.strftime('%y-%b-%d'),'rb') as f:
obj = pickle.load(f)
In Console:
python script.py <---works!
In running IPython (Jupyter) in another folder, it causes a FileNotFound exception.
How can I make any path references within my scripts more robust, without putting the whole extended path?
Thanks in advance!

Since running in the console the way you show works, the Pickles directory must be in the same directory as the script. You can make use of this fact so that you don't have to hard code the location of the Pickles directory, but also don't have to worry about setting the "current working directory" to be the directory containing Pickles, which is what your current code requires you to do.
Here's how to make your code work no matter where you run it from:
with open(os.path.join(os.path.dirname(__file__), 'Pickles', name + '_' + date.strftime('%y-%b-%d')), 'rb') as f:
obj = pickle.load(f)
os.path.dirname(__file__) provides the path to the directory containing the script that is currently running.
Generally speaking, it's a good practice to always fully specify the locations of things you interact with in the filesystem. A common way to do this as shown here.
UPDATE: I updated my answer to be more correct by not assuming a specific path separator character. I had chosen to use '/' only because the original code in the question already did this. It is also the case that the code given in the original question, and the code I gave originally, will work fine on Windows. The open() function will accept either type of path separator and will do the right thing on Windows.

You have to use absolute paths. Also to be cross platform use join:
First get the path of your script using the variable __file__
Get the directory of this file with os.path.dirname(__file__)
Get your relative path with os.path.join(os.path.dirname(__file__), "Pickles", f"{name}_{date.strftime('%y-%b-%d')}")
it gives you:
with open(os.path.join(os.path.dirname(__file__), "Pickles", f"{name}_{date.strftime('%y-%b-%d')}"), 'rb') as f:
obj = pickle.load(f)

File not found from Python although file exists

I'm trying to load a simple text file with an array of numbers into Python. A MWE is
import numpy as np
BASE_FOLDER = 'C:\\path\\'
BASE_NAME = 'DATA.txt'
fname = BASE_FOLDER + BASE_NAME
data = np.loadtxt(fname)
However, this gives an error while running:
OSError: C:\path\DATA.txt not found.
I'm using VSCode, so in the debug window the link to the path is clickable. And, of course, if I click it the file opens normally, so this tells me that the path is correct.
Also, if I do print(fname), VSCode also gives me a valid path.
Is there anything I'm missing?
EDIT
As per your (very helpful for future reference) comments, I've changed my code using the os module and raw strings:
BASE_FOLDER = r'C:\path_to_folder'
BASE_NAME = r'filename_DATA.txt'
fname = os.path.join(BASE_FOLDER, BASE_NAME)
Still results in error.
Second EDIT
I've tried again with another file. Very basic path and filename
BASE_FOLDER = r'Z:\Data\Enzo\Waste_Code'
BASE_NAME = r'run3b.txt'
And again, I get the same error.
If I try an alternative approach,
os.chdir(BASE_FOLDER)
a = os.listdir()
then select the right file,
fname = a[1]
I still get the error when trying to import it. Even though I'm retrieving it directly from listdir.
>> os.path.isfile(a[1])
False

Using the module os you can check the existence of the file within python by running
import os
os.path.isfile(fname)
If it returns False, that means that your file doesn't exist in the specified fname. If it returns True, it should be read by np.loadtxt().
Extra: good practice working with files and paths
When working with files it is advisable to use the amazing functionality built in the Base Library, specifically the module os. Where os.path.join() will take care of the joins no matter the operating system you are using.
fname = os.path.join(BASE_FOLDER, BASE_NAME)
In addition it is advisable to use raw strings by adding an r to the beginning of the string. This will be less tedious when writing paths, as it allows you to copy-paste from the navigation bar. It will be something like BASE_FOLDER = r'C:\path'. Note that you don't need to add the latest '\' as os.path.join takes care of it.

You may not have the full permission to read the downloaded file. Use
sudo chmod -R a+rwx file_name.txt
in the command prompt to give yourself permission to read if you are using Ubuntu.

For me the problem was that I was using the Linux home symbol in the link (~/path/file). Replacing it with the absolute path /home/user/etc_path/file worked like charm.

Opening a CSV from a Different Directory Python

I've been working on a project where I need to import csv files, previously the csv files have been in the same working directory. Now the project is getting bigger so for security and organizational resaons I'd much prefer to keep them in a different directory.
I've had a look at some other questions asking similar things but I couldn't figure out out how to apply them to my code as each time I tried I kept getting the same error message mainly:
IOError: [Errno 2] No such file or directory:
My original attempts all looked something like this:
import csv # Import the csv module
import MySQLdb # Import MySQLdb module
def connect():
login = csv.reader(file('/~/Projects/bmm_private/login_test.txt'))
I changed the path within several times as well by dropping the first / then then the ~ then the / again after that, but each time I got the error message. I then tried another method suggested by several people by importing the os:
import os
import csv # Import the csv module
import MySQLdb # Import MySQLdb module
def connect():
path = r'F:\Projects\bmm_private\login_test.txt'
f = os.path.normpath(path)
login = csv.reader(file(f))
But I got the error message yet again.
Any help here would be much appreciated, if I could request that you use the real path (~/Projects/bmm_private/login_test.txt) in any answers you know of so it's very clear to me what I'm missing out here.
I'm pretty new to python so I may struggle to understand without extra clarity/explanation. Thanks in advance!

The tilde tells me that this is the home folder (e.g. C:\Users\<username> on my Windows system, or /Users/<username> on my Mac). If you want to expand the user, use the os.path.expanduser call:
full_path = os.path.expanduser('~/Projects/bmm_private/login_test.txt')
# Now you can open it
Another approach is to seek for the file in relative to your current script. For example, if your script is in ~/Projects/my_scripts, then:
script_dir = os.path.dirname(__file__) # Script directory
full_path = os.path.join(script_dir, '../bmm_private/login_test.txt')
# Now use full_path

Running python script with new directories

I have recently begun working on a new computer. All my python files and my data are in the dropbox folder, so having access to the data is not a problem. However, the "user" name on the file has changed. Thus, none of my os.chdir() operations work. Obviously, I can modify all of my scripts using a find and replace, but that won't help if I try using my old computer.
Currently, all the directories called look something like this:
"C:\Users\Old_Username\Dropbox\Path"
and the files I want to access on the new computer look like:
"C:\Users\New_Username\Dropbox\Path"
Is there some sort of try/except I can build into my script so it goes through the various path-name options if the first attempt doesn't work?
Thanks!

Any solution will involve editing your code; so if you are going to edit it anyway - its best to make it generic enough so it works on all platforms.
In the answer to How can I get the Dropbox folder location programmatically in Python? there is a code snippet that you can use if this problem is limited to dropbox.
For a more generic solution, you can use environment variables to figure out the home directory of a user.
On Windows the home directory is location is stored in %UserProfile%, on Linux and OSX it is in $HOME. Luckily Python will take care of all this for you with os.path.expanduser:
import os
home_dir = os.path.expanduser('~')
Using home_dir will ensure that the same path is resolved on all systems.

Thought the file sq.py with these codes(your olds):
C:/Users/Old_Username/Dropbox/Path
for x in range:
#something
def Something():
#something...
C:/Users/Old_Username/Dropbox/Path
Then a new .py file run these codes:
with open("sq.py","r") as f:
for x in f.readlines():
y=x
if re.findall("C:/Users/Old_Username/Dropbox/Path",x) == ['C:/Users/Old_Username/Dropbox/Path']:
x="C:/Users/New_Username/Dropbox/Path"
y=y.replace(y,x)
print (y)
Output is:
C:/Users/New_Username/Dropbox/Path
for x in range:
#something
def Something():
#something...
C:/Users/New_Username/Dropbox/Path
Hope its your solution at least can give you some idea dealing with your problem.

Knowing that eventually I will move or rename my projects or scripts, I always use this code right at the beginning:
import os, inspect
this_dir = os.path.dirname(os.path.abspath(inspect.getfile(inspect.currentframe())))
this_script = inspect.stack()[0][1]
this_script_name = this_script.split('/')[-1]
If you call your script not with the full but a relative path, then this_script will also not contain a full path. this_dir however will always be the full path to the directory.

How to set current working directory in python in a automatic way

How can I set the current path of my python file "myproject.py" to the file itself?
I do not want something like this:
path = "the path of myproject.py"
In mathematica I can set:
SetDirectory[NotebookDirectory[]]
The advantage with the code in Mathematica is that if I change the path of my Mathematica file, for example if I give it to someone else or I put it in another folder, I do not need to do anything extra. Each time Mathematica automatically set the directory to the current folder.
I want something similar to this in Python.

The right solution is not to change the current working directory, but to get the full path to the directory containing your script or module then use os.path.join to build your files path:
import os
ROOT_PATH = os.path.dirname(os.path.abspath(__file__))
# then:
myfile_path = os.path.join(ROOT_PATH, "myfile.txt")
This is safer than messing with current working directory (hint : what would happen if another module changes the current working directory after you did but before you access your files ?)

I want to set the directory in which the python file is, as working directory
There are two step:
Find out path to the python file
Set its parent directory as the working directory
The 2nd is simple:
import os
os.chdir(module_dir) # set working directory
The 1st might be complex if you want to support a general case (python file that is run as a script directly, python file that is imported in another module, python file that is symlinked, etc). Here's one possible solution:
import inspect
import os
module_path = inspect.getfile(inspect.currentframe())
module_dir = os.path.realpath(os.path.dirname(module_path))

Use the os.getcwd() function from the built in os module also there's os.getcwdu() which returns a unicode object of the current working directory
Example usage:
import os
path = os.getcwd()
print path
#C:\Users\KDawG\Desktop\Python