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Python for Data Analysis, Chapter 2, first example

I'm following along with the examples in a translated version of Wes McKinney's "Python for Data Analysis" and I was blocked in first example of Chapter 2
I think my problem arose because I saved a data file in a wrong path. is that right?
I stored a file, usagov_bitly_data2012-03-16-1331923249.txt, in C:\Users\HRR
and also stored folder, pydata-book-mater, that can be downloaded from http://github.com/pydata-book in C:\Users\HRR\Anaconda2\Library\bin.

Depends.
You might change the location you save your File or eddit the path you give to your code in Line 10. Since you're yousing relativ Paths i guess your script runs in C:\Users\HRR\Anaconda2\Library\bin, which means you have to go back to C:\Users\HRR or use an absolute Path ... or move the File, but hell you don't want to move a file every time you want to open it, like moving word files into msoffice file to open it, so try to change the Path.
And allways try harder ;)

In python open() will open from the current directory down unless given a full path (in linux that starts with / and windows <C>://). In your case the command is open the folder ch02 in the directory the script is running from and then open usagov_bitly_data2012-03-16-1331923249.txt in that folder.
Since you are storing the text file in C:\Users\HRR\usagov_bitly_data2012-03-16-1331923249.txt and you did not specify the directory of the script. I recommend the following command instead open(C:\\Users\\HRR\\usagov_bitly_data2012-03-16-1331923249.txt)
Note: the double \ is to escape the characters and avoid tabs and newlines showing up in the path.

Python raw input directory that has a space is not working?

When I prompt the user for a directory using raw_input, it works as long as I have a folder that doesn't have a space in it. new_folder for example works fine but new folder does not work when I use os.path.isdir.
I know I could just replace the spaces with no space but then that leads to problems down the road as I'm using the absolute path for things later on. So if I change the actual folder name, it's not going to work.
file_directory = raw_input("Drag in a directory:")
if os.path.isdir(file_directory):
print 'This is a directory'
else:
print '\nYou did not enter a directory. Please input a directory, not a file\n'
Why doesn't os.path.isdir see a folder with a space as a directory and how can I fix it?
**edit I forgot to mention this is when I run the script in the command line. When I drag in a folder with no spaces, rawinput equals a string with no quotes. When I drag in a folder with spaces it puts quotes around the input which I think is what's messing it up.

#jasonharper advised me that "The ability to drag a file/folder into a console window exists primarily to support the command line, which requires quotes (or other form of escaping) for pathnames including spaces".
so raw_input().strip('"') solved the problem.

Playing Audio with subprocess.call in Python

I wanted to play a .wav file, without using external modules, and i read i could do that using this:
def play(audio_file_path):
subprocess.call(["ffplay", "-nodisp", "-autoexit", /Users/me/Downloads/sample.wav])
I however get:
SyntaxError: invalid syntax
If i use os.path.realpath to get the absolute path of the file, i get just the same thing. (The path i see at get info)
Environment is OSX, Python 2.7
Can someone tell me what i am doing wrong? I am new to Python (and to Programming).

There are multiple problems.
Indentation
Code inside the function should be indented, to show that it is part of the function
File name should be in a quotes
It should be a string
It should be:
def play(audio_file_path):
subprocess.call(["ffplay", "-nodisp", "-autoexit", "/Users/me/Downloads/sample.wav"])

os.listdir can't see my directory

I am working on a python script that installs an 802.1x certificate on a Windows 8.1 machine. This script works fine on Windows 8 and Windows XP (haven't tried it on other machines).
I have isolated the issue. It has to do with clearing out the folder
"C:\Windows\system32\config\systemprofile\AppData\LocalLow\Microsoft\CryptURLCache\Content"
The problem is that I am using the module os and the command listdir on this folder to delete each file in it. However, listdir errors, saying the folder does not exist, when it does indeed exist.
The issue seems to be that os.listdir cannot see the LocalLow folder. If I make a two line script:
import os
os.listdir("C:\Windows\System32\config\systemprofile\AppData")
It shows the following result:
['Local', 'Roaming']
As you can see, LocalLow is missing.
I thought it might be a permissions issue, but I am having serious trouble figuring out what a next step might be. I am running the process as an administrator from the command line, and it simply doesn't see the folder.
Thanks in advance!
Edit: changing the string to r"C:\Windows\System32\config\systemprofile\AppData", "C:\Windows\System32\config\systemprofile\AppData", or C:/Windows/System32/config/systemprofile/AppData" all produce identical results
Edit: Another unusual wrinkle in this issue: If I manually create a new directory in that location I am unable to see it through os.listdir either. In addition, I cannot browse to the LocalLow or my New Folder through the "Save As.." command in Notepad++
I'm starting to think this is a bug in Windows 8.1 preview.

I encountered this issue recently.
I found it's caused by Windows file system redirector
and you can check out following python snippet
import ctypes
class disable_file_system_redirection:
_disable = ctypes.windll.kernel32.Wow64DisableWow64FsRedirection
_revert = ctypes.windll.kernel32.Wow64RevertWow64FsRedirection
def __enter__(self):
self.old_value = ctypes.c_long()
self.success = self._disable(ctypes.byref(self.old_value))
def __exit__(self, type, value, traceback):
if self.success:
self._revert(self.old_value)
#Example usage
import os
path = 'C:\\Windows\\System32\\config\\systemprofile\\AppData'
print os.listdir(path)
with disable_file_system_redirection():
print os.listdir(path)
print os.listdir(path)
ref : http://code.activestate.com/recipes/578035-disable-file-system-redirector/

You must have escape sequences in your path. You should use a raw string for file/directory paths:
# By putting the 'r' at the start, I make this string a raw string
# Raw strings do not process escape sequences
r"C:\path\to\file"
or put the slashes the other way:
"C:/path/to/file"
or escape the slashes:
# You probably won't want this method because it makes your paths huge
# I just listed it because it *does* work
"C:\\path\\to\\file"

I'm curious as to how you are able to list the contents with those two lines. You are using escape sequences \W, \S, \c, \s, \A in your code. Try escaping the back slash like this:
import os
os.listdir('C:\\Windows\\System32\\config\\systemprofile\\AppData')

how to check for platform incompatible folder (file) names in python

I would like to be able to check from python if a given string could be a valid cross platform folder name - below is the concrete problem I ran into (folder name ending in .), but I'm sure there are some more special cases (e.g.: con, etc.).
Is there a library for this?
From python (3.2) I created a folder on Windows (7) with a name ending in dot ('.'), e.g. (without square brackets): [What I've done on my holidays, Part II.]
When the created folder was ftp'd (to linux, but I guess that's irrelevant), it did not have the dot in it anymore (and in return, this broke a lot of hyperlinks).
I've checked it from the command line, and it seems that the folder doesn't have the '.' in the filename
mkdir tmp.
dir
cd tmp
cd ..\tmp.
Apparently, adding a single dot at the end of the folder name is ignored, e.g.:
cd c:\Users.
works just as expected.

Nope there's sadly no way to do this. For windows you basically can use the following code to remove all illegal characters - but if someone still has a FAT filesystem you'd have to handle these too since those are stricter. Basically you'll have to read the documentation for all filesystem and come up with a complete list. Here's the NTFS one as a starting point:
ILLEGAL_NTFS_CHARS = "[<>:/\\|?*\"]|[\0-\31]"
def __removeIllegalChars(name):
# removes characters that are invalid for NTFS
return re.sub(ILLEGAL_NTFS_CHARS, "", name)
And then you need some "forbidden" name list as well to get rid of COM. Pretty much a complete mess that.. and that's ignoring linux (although there it's pretty relaxed afaik)

Do not end a file or directory name with a space or a period. Although
the underlying file system may support such names, the Windows shell
and user interface does not.
http://msdn.microsoft.com/en-us/library/aa365247.aspx#naming_conventions
That page will give you information about other illegal names too, for Windows that is. Including CON as you said your self.
If you respect those (seemingly harsh) rules, I think you'll be safe on Linux and most other systems too.