Doubled backslashes in Windows paths

[Stephen Tucker]

Hi Oz,

This might only be tangential to your actual issue, but, there again, it
might be the tiny clue that you actually need.

In Python, I use raw strings and single backslashes in folder hierarchy
strings to save the problem of the backslash in ordinary strings. Even with
this policy, however, there is a slight "gotcha": Although it is claimed
that r" ... " suspends the escape interpretation of the backslash in the
string, a raw string cannot end with a backslash:

   myraw = "\a\b\"

provokes the error message:

   SyntaxError: EOL while scanning string literal

To see how well this approach deals with folder hierarchies with spaces in
their names, I created the following file:

c:\Python27\ArcGIS10.4\Lib\idlelib\sjt\sp in\test.txt

Note the space in the folder name  sp in .

In IDLE, I then issued the following statement:

infile= open (r"c:\Python27\ArcGIS10.4\Lib\idlelib\sjt\sp in\test.txt", "r")

Note that I didn't need to get enclosing quotes into my folder hierarchy
string. It begins with  c  and ends with  t .

The statement worked as you might expect, and granted me access to the
lines in the file.

It seems that it is only necessary to enclose a folder hierarchy string in
quotes when defining the string in a situation in which spaces would
otherwise be interpreted as terminators. The classis case of this is in a
command with parameters in a batch file. If the string has been defined
before it is presented to the Windows Command interpreter, the spaces are
accepted as part of it without the need then of enclosing quotes.

Hope this helps.

Yours,

Stephen Tucker.


On Fri, Oct 7, 2016 at 6:30 AM, Oz-in-DFW <lists at ozindfw.net> wrote:

> I'm using Python 3.5.2 (v3.5.2:4def2a2901a5, Jun 25 2016, 22:01:18) [MSC
> v.1900 32 bit (Intel)] on Windows 7
>
> I'm trying to write some file processing that looks at file size,
> extensions, and several other things and I'm having trouble getting a
> reliably usable path to files.
>
> The problem *seems* to be doubled backslashes in the path, but I've read
> elsewhere that this is just an artifact of the way the interpreter
> displays the strings.
>
> I'm getting an error message on an os.path.getsize call;
>
>     Path: -
>     "C:\Users\Rich\Desktop\2B_Proc\2307e60da6451986dd8d23635b845386.jpg" -
>     Traceback (most recent call last):
>       File "C:\Users\Rich\workspace\PyTest\test.py", line 19, in <module>
>         if os.path.getsize(path)>10000:
>       File "C:\Python32\lib\genericpath.py", line 49, in getsize
>         return os.stat(filename).st_size
>     WindowsError: [Error 123] The filename, directory name, or volume
>     label syntax is incorrect:
>     '"C:\\Users\\Rich\\Desktop\\2B_Proc\\2307e60da6451986dd8d23635b8453
> 86.jpg"'
>
> From (snippet)
>
>                 path = '"'+dirpath+name+'"'
>                 path = os.path.normpath(path)
>                 print("Path: -",path,"-")
>                 if os.path.getsize(path)>10000:
>                     print("Path: ",path," Size:
>     ",os.path.getsize(dirpath+name))
>
> but if I manually use a console window and cut and paste the path I
> print, it works;
>
>     C:\>dir
>     "C:\Users\Rich\Desktop\2B_Proc\2307e60da6451986dd8d23635b845386.jpg"
>      Volume in drive C is Windows7_OS
>
>      Directory of C:\Users\Rich\Desktop\2B_Proc
>
>     10/03/2016  08:35 AM            59,200
>     2307e60da6451986dd8d23635b845386.jpg
>                    1 File(s)         59,200 bytes
>                    0 Dir(s)  115,857,260,544 bytes free
>
> So the file is there and the path is correct. I'm adding quotes to the
> path to deal with directories and filenames that have spaces in them.
> If I drop the quotes, everything works as I expect *until* I encounter
> the first file/path with spaces.
>
> I'll happily RTFM, but I need some hints as to which FM to R
>
> --
> mailto:oz at ozindfw.net
> Oz
> POB 93167
> Southlake, TX 76092 (Near DFW Airport)
>
>
>
> --
> https://mail.python.org/mailman/listinfo/python-list
>