Develop Reference

Python Os Changing Path

I'm trying to change directory when calling a python file in cmd but it's not working !
I tried all types of slashes & back slashes & escaping, sometimes when the code runs, the directory isn't changing and stays the same where i start the py file and sometimes the code isn't running and i have this error Error
import os
#import sys
os.chdir('%SystemRoot%/Users/%username%/AppData/Local/Google/Chrome/User Data')
os.system('cd \"%SystemRoot%\\Users\\%username%\\AppData\\Local\\Google\\Chrome\\User Data\"')
I tried to change the system variables %SystemRoot% and %username% to words like C:/ and user2 (my system root and user name ) but still not working !
Can anyone try it in his computer and tell me what to change pls ?
Thanks !

Python does not automatically expand shell variables like %SystemRoot% and %username% to their actual values, this is what caused the error you were getting. Try os.chdir(os.path.expandvars(os.path.expanduser('%SystemRoot%/Users/%username%/AppData/Local/Google/Chrome/User Data'))) for the first line as this should expand the %username% and %SystemRoot% variables to a valid path.
EDIT: Sorry, I misunderstood your question. While this will take care of the error you were getting, you cannot change the shell's working directory from your script; see comment under your question by Ulrich Eckhardt

Execute Knime with multiple arguments in Python (subprocess.run)

Hello all,
i'm looking for a way to execute a KNIME workflow in Python in batch mode (without opening the GUI of KNIME, https://www.knime.com/faq#q12)
After hours of trying I am asking you whether you can help me in this case:
When I run the python file, it opens the Knime exe, after some seconds the knime GUI is also opened. Unfortunately, the exe is not excuting the workflow (for testing the workflow should read an csv file and save it in another file destination)
This is actual code in python 3.7:
import subprocess
subprocess.run(["C:/Program Files/KNIME/knime.exe","-consoleLog","-nosplash","-noexit","-nosave","-reset","-application org.knime.product.KNIME_BATCH_APPLICATION","-workflowDir= C:/Users/jssch/knime-workspace/testexecute"]
When i paste the following code in command line the code is working and is executed correctly (it just hands over the arguments and does not open the knime GUI):
C:\Program Files\KNIME\knime.exe" -consoleLog -noexit -nosplash -nosave -reset -application org.knime.product.KNIME_BATCH_APPLICATION -workflowDir="C:\Users\jssch\knime-workspace\testexecute"
Thanks for your help in advance!

I think you made a mistake with the -application part, they should be in different Strings. Also the -workflowDir= C:/... seems to have an extra space too.
The problematic part:
"-application org.knime.product.KNIME_BATCH_APPLICATION"
it should be:
"-application", "org.knime.product.KNIME_BATCH_APPLICATION"
Probably you do not want the -noexit argument either.
All together:
import subprocess
subprocess.run(["C:/Program Files/KNIME/knime.exe", "-consoleLog", "-nosplash", "-nosave", "-reset", "-application", "org.knime.product.KNIME_BATCH_APPLICATION", "-workflowDir=C:/Users/jssch/knime-workspace/testexecute"]
(I usually prefer the paths without spaces, strange characters, I would use a KNIME installation from a different path, though this is fine too.)

Running Batch File from Python

I am trying to run a batch file through python; however, it is not recognizing the path. It stops reading the path after the space between 'Practice' and 'Folder'. How can I fix this? I've tried the r and using forward and backward slashes. Any help would be awesome. Thank you!
import os
Practice = r"C:\Users\Username\Desktop\Practice Folder\Practice.bat"
os.system(Practice)
'C:\Users\Username\Desktop\Practice' is not recognized as an internal
or external command, operable program or batch file.

Change working directory to the script directory as you are using some relative redirection paths. Pushd changes current directory to any drive and can map network drives. The && chains commands and only runs the right hand command if the left hand command succeeds. %UserProfile% is a standard environmental variable which is usually better then using a fixed path of C:\Users\Username.
import os
Practice = r'pushd "%UserProfile%\Desktop\Practice Folder" && Practice.bat'
os.system(Practice)

Try using call from subprocess module.
You need to enclose the command only in double quotes.
from subprocess import call
call(r'"C:\Users\Username\Desktop\Practice Folder\Practice.bat"')
(Notice the order of placing quotes...)
This would even work with os.system() provided you take care the order of quotation marks.
from os import system
system(r'"C:\Users\Username\Desktop\Practice Folder\Practice.bat"')
This should help fix your problem.

You probably need to use two types of quotation marks e.g.
import os
Practice = r"'C:\Users\Username\Desktop\Practice Folder\Practice.bat'"
os.system(Practice)
As it is, your string does not contain quotation marks - you need to include quotation marks within your string or else Windows will think that Folder\Practice.bat is an argument to the command rather than a continuation of the file path

Try this
import os
Practice = os.path.abspath(r"C:\Users\Username\Desktop\Practice Folder\Practice.bat")
Edit:
Something like this worked for me
os.system(r'"C:\Users\Username\Desktop\Practice Folder\Practice.bat"')

Open windows explorer at a specific network location in Python

I have tried so many variants of a theme to get this explorer window open at the P:\ drive, from what my little knowledge tells me, the fact the path to the folder is anywhere but the C:\ drive means it fails (it works with C:) so perhaps the path is wrong? the code below shows some of the tries i have made but still no luck, "P:" is mapped the same on all machines.
def Open_Win_Explorer_and_Select_Dir():
import subprocess
fldrname = os.path.basename(currentproject.get())
print(fldrname)
#subprocess.Popen('c:\windows\EXPLORER.EXE', cwd=(P:/Projects 2013/)
#subbprocess.Popen('c:\\windows\\EXPLORER.EXE' cwd=('P:\\Projects_2013\\')fldrname)
#subprocess.Popen(r'C:/Windows/explorer.exe', cwd=r'//WRDBSVR/Project_Data/Projects_2013/'+fldrname)
subprocess.Popen('explorer /n, /select r"\\192.168.0.27\\Project_Data\\Projects_2013\\"'+fldrname)
#subprocess.Popen('explorer /n, /select r"P:\\Project_Data\\Projects_2013\\"'+fldrname)

well to open My pc (for windows) try:
import subprocess
subprocess.Popen('explorer ""')
"#if subprocess.Popen('explorer "{0}".format(full_path)') is struck at pc\my documents.
where full_path=os.path.join("your/path")"

Appart from the fact that Ashish Nitin Patil's answer is definitly better, as using a variable for paths is always a good idea, you have a problem with your quotes:
# This line is not correct
'explorer /n, /select r"\\192.168.0.27\\Project_Data\\Projects_2013\\"'+fldrname
# ^you start a new string without ending previous one
# this one is correct
'explorer /n, /select ' + r'\192.168.0.27\Project_Data\Projects_2013\' + fldrname
# ^first ending string start
Besides, using raw strings (r"xxx") means that \ will not escape characters, so you shall not double them. If you want to double them, you do not need prepend r.
Last remark: take care to avoid string concatenation (+) when working with paths; you should use os.path.join() instead.

Following should do the job.
import subprocess
subprocess.Popen('explorer "{0}"'.format(full_folder_path))
Update -
Tested on my system -
full_path = os.path.join("P:/Project_Data/Projects_2013/",fldrname)
print full_path # Verify that it is correct
subprocess.Popen('explorer "{0}"'.format(full_path))

Dropping a file onto a python script in windows - avoid Windows use of backslashes in the argument

I know all about how Windows uses backslashes for filenames, etc., and Unix uses forward. However, I never use backslashes with strings I create in my code. However:
When windows explorer "drops" a file onto a python script, the string it passes contains backslashes. These translate into escape sequences in the strings in the sys.argv list and then I have no way to change them after that (open to suggestions there)
Is there any way I can somehow make windows pass a literal string or ... any other way I can solve this problem?
I'd love my script to be droppable, but the only thing preventing me is windows backslashes.
EDIT:
Sorry everyone, the error was actually not the passing of the string - as someone has pointed out below, but this could still help someone else:
Make sure you use absolute path names because when the Windows shell will NOT run the script in the current directory as you would from a command line. This causes permission denied errors when attempting to write to single-part path-names that aren't absolute.

Cannot reproduce. This:
import os, sys
print sys.argv
print map(os.path.exists, sys.argv)
raw_input()
gives me this:
['D:\\workspaces\\generic\\SO_Python\\9266551.py', 'D:\\workspaces\\generic\\SO_Python\\9254991.py']
[True, True]
after dropping the second file onto the first one. Python 2.7.2 (on Windows). Can you try this code out?