Develop Reference

Can't replace character "\"

I've been working on a program that reads out an specific PDF and converts the data to an Excel file. The program itself already works, but while trying to refine some aspects I ran into a problem. What happens is the modules I'm working with read directories with simple slashes dividing each folder, such as:
"C:/Users/UserX"
While windows directories are divided by backslashes, such as:
"C:\Users\UserX"
I thought using a simple replace would work just fine:
directory.replace("\" ,"/")
But whenever I try to run the program, the \ isn't identified as a string. Instead it pops up as orange in the IDE I'm working with (PyCharm). Is there anyway to remediate this? Or maybe another useful solution?

In general you should work with the os.path package here.
os.getcwd() gives you the current directory, you can add a subfolder of it via more arguments, and put the filename last.
import os
path_to_file = os.path.join(os.getcwd(), "childFolder", filename)

In Python, the '\' character is represented by '\\':
directory.replace("\\" ,"/")

Just try adding another backslash.
First of all you need to pass "C:\Users\UserX" as a raw string. Use
directory=r"C:\Users\UserX"
Secondly, suppress the backslash using a second backslash.
directory.replace("\\" ,"/")
All of this is required as in python the backslash (\) is a special character known as an escape character.

Try this:
import os
path = "C:\\temp\myFolder\example\\"
newPath = path.replace(os.sep, '/')
print(newPath)
Output:<< C:/temp/myFolder/example/ >>

Adding paths to arguments in popen

I want to execute a Linux command through Python. This works in the terminal:
/usr/bin/myprogram --path "/home/myuser"
I've tried this:
path = "/home/myuser"
args = ['/usr/bin/myprogram', '--path ' + path]
proc = subprocess.Popen(args)
And this:
path = "/home/myuser"
args = ['/usr/bin/myprogram', '--path "' + path + '"']
proc = subprocess.Popen(args)
But myprogram does not accept the path formatting. I know that paths behave differently when not executing as shell but I can't get it working. I've also tried single quoting the path instead of double quoting it. Bonus points for a solution that also works on Windows (with a different program path, obviously).
EDIT: Sorry, was writing this out from memory and used backslashes instead of forward slashes. The actual code did use the (correct) forward slashes.

Here's something to try:
import subprocess
import shlex
p = subprocess.Popen(shlex.split("/usr/bin/myprogram --path /home/myuser")
Mind the forward slashes ("/"). From what I read, Python doesn't like backslashes ("\") even when running on Windows (I've never used it on Windows myself).

The problem comes from your string literal, '\usr\bin\myprogram'. According to escaping rules, \b is replaced by \x08, so your executable is not found.
Pun an r in front of your string literals (i.e. r'\usr\bin\myprogram'), or use \\ to represent a backslash (i.e. '\\usr\\bin\\myprogram').

python: os.walk of e drive does not work

Simple code:
import os
filenamelist = []
#path = "E:\blah\blah\blah"
path = "C:\Program Files\Console2"
for files in os.walk(path):
filenamelist.append(files)
print files
The above works. But when I set path= "E:\blah\blah\blah" the script runs but returns nothing.
1) C:\Users\guest>python "read files.py"
('C:\\Program Files\\Console2', [], ['console.chm', 'Console.exe', 'console.xml', 'ConsoleHook.dll', 'FreeImage.dll', 'FreeImagePlus.dll'])
2) C:\Users\guest>python "read files.py"
C:\Users\guest>
Any idea why os.walk() is having a difficult time with E:\? I can't get it to read anything on E:. I have an external drive mapped to E drive.

That could be because python treats \ as an escape symbol and you have a combination that is really an escape symbol for E: disk path.
It might be solved in one of the following ways:
Raw string literals: r"E:\blah\blah\blah" (the backslashes are not treated as escape symbols).
Double-backslashes: "E:\\blah\\blah\\blah" (escape symbols are escaped by themselves).
Slashes "E:/blah/blah/blah" (this works on Windows too).

python and windows double backslash

I got a program running on my local machine which uses some files. I create the reference to the files by using: os.path.join( tempfile.gettempdir(), 'filename.txt' )
After that I'm running a program which accepts some parameters --log-file filepath where filepath is one of the files I just explained above.
On my machine python creates backslashes for the paths but not double backslashes and the program complains because it's considered an escape character and should be a double backslash.
Is there any standard way of making sure that I get a working path with double backslashes in python? I could use regex but I would prefer something similar to what os. provides. Maybe I'm missing something.
I'm calling the program using subprocess.Popen:
self._proc = subprocess.Popen( command.split( ' ' ) )
where command is something like pcix.exe --log-file file_path
Also, running a test on my console shows that my python does not produce double backslash for paths:
>>> print os.path.join(tempfile.gettempdir(), "test.txt")
c:\users\manilo~1\appdata\local\temp\test.txt
Leaving out the print command produces the same path:
>>> os.path.join(tempfile.gettempdir(), "test.txt")
c:\users\manilo~1\appdata\local\temp\test.txt
Any idea why?
P.S. The platform i'm running is CPython

Try:
print os.path.join(tempfile.gettempdir(), "test.txt").replace('\\\\','\\\\\\\\')

How to copy file to path that contains ampersand '&' using Python's shutil?

I am complete newbie in Python and have to modify existing Python script. The script copies file to other path like following:
err=shutil.copyfile(src, dst)
This works unless dst contains character like &:
dst = "Y:\R&D\myfile.txt"
In this case I get windows error popup that says
Open file or Read file error
Y:\R
I tried to escape & using back slash, double back slash and wrapping the string with additional quotes: dst = "\"Y:\R&D\myfile.txt\"".
Nothing works in last case I get "invalid path" error message from shutil.
How can I solve this problem?

I doubt that ampersand is supported on most platforms. You will likely have to make a call to a windows specific program. I suggest robocopy since its really good at copying files. If it's not included in your version of windows, you can find it in the windows server administrator toolkit for 2003.

It works for me if I change all the \ in the filepaths to / (in both src and dst strings). Yes, I know you're using Windows, but filepaths always seem to be less fussy in Python if you use /, even in Windows.
Also, it looks like you're copying to a network drive. Do you get the same problem copying to c:\R&D\?
What flavor of Windows are you using? shutil.copyfile() works fine for me with & in directory names, in both src and dst paths, in both local and network drives on XP -- as long as I use / in place of \.

Easiest solution, signify to python that the string is raw and not to escape it or modify it in any way:
import shutil
src = r"c:\r&d\file.txt"
dst = r"c:\r&d\file2.txt"
err=shutil.copyfile(src, dst)

Try to escape the "\" with "\ \", this command must work (for example):
shutil.copyfile("Y:\\R&D\\myfile.txt", "C:\\TMP")

Here are few ways to make it work on windows:
Approach 1: (already explained)
import shutil; shutil.copy(src,dest)
as long as src/dest are using r'c:\r&d\file' string format. It also works with forward "/" slashes as well.
Approach 2: Notice use of double quotes instead of single quotes on windows.
src = r'c:\r & d\src_file'
os.system('copy "{}" "{}"'.format(src,dest))
1 file(s) copied
Last resort:
with open(dest, 'wb') as f:
f.write(open(src,'rb').read())
Unlike os.system, this preferred implementation subprocess.call could not work with any quoting approach on windows. I always get The specified path is invalid. Did not try on unix.