I'm getting the name of a file in Django after an Image save :
path-> 'companies/92_dsa/log/Hydrangeas.jpg' as it is in database
I do a clone of the file, an resize (is an image) and want to save the new file with a different name.
I get the directory of the original file:
folder = os.path.dirname(path)
the filename and extension:
filename, extension = os.path.splitext(os.path.basename(media_path))
then create a
new_filename = filename + '_sz' + extension
and the I want to recreate the path:
new_path = os.path.join(folder, new_filename)
and the problem(slash-backslash before the filename):
'companies/94_sda/logos\Hydrangeas_sz.jpg'
I'm working in Windows, bur the final deploy probably will be on Linux, so I want a fix indifferent of the OS.
so I want a fix indifferent of the OS.
Unfortunately, you can't really have your cake and eat it.
You say that
I'm working in Windows, bur the final deploy probably will be on Linux
This implies you are running the program on Windows, but dealing with *nix file names (be it Linux, Unix, or mac OS).
To do this completely os-independent ... you would need to split the original path on "/" to get all the sub components and then re-join them with os.path.join.
But then you need to deal with the fact that directory structures for absolute paths are very different between the two OS's - not to mention the leading drive specifier on Windows. This is less of an issue if you are only dealing with relative paths.
In short, the root of your problem is that the database contains Linux-style paths and you are processing them on Windows. You would have a similar problem if it was the other way around.
You need to choose your deployment platform and code for it.
Alternatively, write your code to simply remove the extension from the full path and replace it with "_sz."+extension
Since you don't actually care about the path in relation to the host OS (because you've chosen to store paths POSIX style in your DB), you can just use string joining: new_path = '/'.join([folder, new_filename]), or you could import the posixpath module directly import posixpath; new_path = posixpath.join(folder, new_filename).
You could also investigate PathLib, though that may be overkill for you.
Related
I'm trying to learn how to edit files, but I'm a bit of a python novice, and not all that bright, so when I get a FileNotFoundError I can't figure out how to fix it despite several searches on the interwebz.
import os
old = 'Users\My Name\Pictures\2013\182904_10201130467645938_341581100_n'
new = 'Users\My Name\Pictures\2013\Death_Valley_1'
os.rename(old, new)
'Users\My Name\Pictures\2013\182904_10201130467645938_341581100_n' is a relative path.
Unless you are running your code from the directory that contains the Users dir (which if you are using Windows would most probably be the root C: dir), Python isn't going to find that file.
You also have to make sure to include the file extension if it has any.
There are few ways to solve this, the easiest one will be to use the absolute paths in your code, ie 'C:\Users\My Name\Pictures\2013\182904_10201130467645938_341581100_n.jpg'.
You will also want to use r before the paths, so you want need to escape every \ character.
import os
old = r'C:\Users\My Name\Pictures\2013\182904_10201130467645938_341581100_n.jpg'
new = r'C:\Users\My Name\Pictures\2013\Death_Valley_1.jpg'
os.rename(old, new)
This of course assumes your drive letter is C.
python has recently added the pathlib module (which i like a lot!).
there is just one thing i'm struggling with: is it possible to normalize a path to a file or directory that does not exist? i can do that perfectly well with os.path.normpath. but wouldn't it be absurd to have to use something other than the library that should take care of path related stuff?
the functionality i would like to have is this:
from os.path import normpath
from pathlib import Path
pth = Path('/tmp/some_directory/../i_do_not_exist.txt')
pth = Path(normpath(str(pth)))
# -> /tmp/i_do_not_exist.txt
but without having to resort to os.path and without having to type-cast to str and back to Path. also pth.resolve() does not work for non-existing files.
is there a simple way to do that with just pathlib?
is it possible to normalize a path to a file or directory that does not exist?
Starting from 3.6, it's the default behavior. See https://docs.python.org/3.6/library/pathlib.html#pathlib.Path.resolve
Path.resolve(strict=False)
...
If strict is False, the path is resolved as far as possible and any remainder is appended without checking whether it exists
As of Python 3.5: No, there's not.
PEP 0428 states:
Path resolution
The resolve() method makes a path absolute, resolving
any symlink on the way (like the POSIX realpath() call). It is the
only operation which will remove " .. " path components. On Windows,
this method will also take care to return the canonical path (with the
right casing).
Since resolve() is the only operation to remove the ".." components, and it fails when the file doesn't exist, there won't be a simple means using just pathlib.
Also, the pathlib documentation gives a hint as to why:
Spurious slashes and single dots are collapsed, but double dots ('..')
are not, since this would change the meaning of a path in the face of
symbolic links:
PurePath('foo//bar') produces PurePosixPath('foo/bar')
PurePath('foo/./bar') produces PurePosixPath('foo/bar')
PurePath('foo/../bar') produces PurePosixPath('foo/../bar')
(a naïve approach would make PurePosixPath('foo/../bar') equivalent to PurePosixPath('bar'), which is wrong if foo is a symbolic link to another directory)
All that said, you could create a 0 byte file at the location of your path, and then it'd be possible to resolve the path (thus eliminating the ..). I'm not sure that's any simpler than your normpath approach, though.
If this fits you usecase(e.g. ifle's directory already exists) you might try to resolve path's parent and then re-append file name, e.g.:
from pathlib import Path
p = Path()/'hello.there'
print(p.parent.resolve()/p.name)
Old question, but here is another solution in particular if you want POSIX paths across the board (like nix paths on Windows too).
I found pathlib resolve() to be broken as of Python 3.10, and this method is not currently exposed by PurePosixPath.
What I found worked was to use posixpath.normpath(). Also found PurePosixPath.joinpath() to be broken. I.E. It will not join ".." with "myfile.txt" as expected. It will return just "myfile.txt". But posixpath.join() works perfectly; will return "../myfile.txt".
Note this is in path strings, but easily back to pathlib.Path(my_posix_path) et al for an OOP container.
And easily transpose to Windows platform paths too by just constructing this way, as the module takes care of the platform independence for you.
Might be the solution for others with Python file path woes..
Is it possible to open a file for reading in a sub directory without having to use os.listdir()? Something like this maybe?
f1 = open('/SCRIPT/PYTHON/monomer-b/{}'.format(xyzfile)).read()
I am running the python script in /SCRIPT/PYTHON the files that I want to call is in /SCRIPT/PYTHON/monor-b. Any suggestions
You can use relative paths while opening files in python:
import os
file_content = open(os.path.join('./monomer-b', xyzfile)).read()
Also, by default all paths looks up starting at current directory, so the './' part of subdir name is not necessary. Using os.path.join is better practice than string concatenation or formatting, because it use correct path separators and another OS-specific things.
I'm doing a program in which Chimera needs to be opened, I'm opening it with:
def generate_files_bat(filename):
f = open(filename, 'w')
text = """echo off SET PATH=%PATH%;"C:\\Program Files (x86)\\Chimera 1.6.1\\bin" chimera colpeps.cmd"""
print >>f, text
f.close()
But I need to find Chimera apart from the computer the python program is running. Is there any way the path can be searched by the python program in any computer?
Generally speaking, I don't think it is such a good idea to search the path for a program. Imagine, for example that two different versions were installed on the machine. Are-you sure to find the right one? Maybe a configuraition file parsed with the standard module ConfigParser would be a better option?
Anyway, to go back to your question, in order to find a file or directory, you could try to use os.walk which recursively walks trough a directory tree.
Here is an example invoking os.walk from a generator, allowing you to collect either the first or all matching file names. Please note that the generator result is only based on file name. If you require more advanced filtering (say, to only keep executable files), you will probably use something like os.stat() to extend the test.
import os
def fileInPath(name, root):
for base, dirs, files in os.walk(root):
if name in files:
yield os.path.join(base, name)
print("Search for only one result:")
print(next(fileInPath("python", "/home/sylvain")))
print("Display all matching files:")
print([i for i in fileInPath("python", "/home/sylvain")])
There is which for Linux and where for Windows. They both give you the path to the executable, provided it lies in a directory that is 'searched' by the console (so it has to be in %PATH% in case of Windows)
There is a package called Unipath, that does elegant, clean path calculations.
Have look here for the AbstractPath constructor
Example:
from unipath import Path
prom_dir = Path(__file__)
Currently on a project that my client needs the reference file path to
remain in linux format. For example
A.ma , referencing objects from --> //linux/project/scene/B.ma
B.ma , referencing objects from --> //linux/project/scene/C.ma
Most of our Maya license here however are on Windows. I can run a
Python script that convert all the paths windows paths and save the
file. For example
Z:\project\scene\B.ma
However I'm trying to figure out a way to do this without converting
or altering the original file.... I'll try to explain what I'm trying to do.
Run the script to open the file.
The script checks for the linux formatted reference path, and all
child path down the hierarchy.
Maps all paths to their appropriate windows formatted paths.
Giving the animators the ability to "save" files normally without running a separate save script.
Is this possible to achieve this with Python script? Or will I need a
fully-compiled plug in to get this to work?
Any suggestion is greatly appreciated.
edit: Thank you for your input.
A little more clarification. The projects were set up for us by a remote company and part of the requirement is that we have to keep the path as is. They come as absolute path and we have no choice in that matter.
We match the mount //linux/ on our Fedora workstations. That same drive is mapped to Z:\ on our windows workstations. We only have 2 Maya license for Linux tho which is why I'm trying to do this.
Here is a solution. First step is to create a dict that keeps track of linux/windows references (don't forget to import the re module for regexp):
>>> def windows_path(path):
return path.replace('//linux', 'Z:').replace('/', '\\')
>>> reg = re.compile('(\w+\.ma) , referencing objects from --> (.*)')
>>> d = {}
>>> for line in open('D:\\temp\\Toto.txt'):
match = reg.match(line)
if match:
file_name = match.groups()[0]
linux_path = match.groups()[1]
d[file_name] = (linux_path, windows_path(linux_path))
>>> d
{'B.ma': ('//linux/project/scene/C.ma', 'Z:\\project\\scene\\C.ma'),
'A.ma': ('//linux/project/scene/B.ma', 'Z:\\project\\scene\\B.ma')}
Then you just need to loop on this dict to ask for file save:
>>> for file_name in d.keys():
s = raw_input('do you want to save file %s ? ' % file_name)
if s.lower() in ('y', 'yes'):
# TODO: save your file thanks to d[file][0] for linux path,
# d[file][1] for windows path
print '-> file %s was saved' % file_name
else:
print '-> file %s was not saved' % file_name
do you want to save file B.ma ? n
-> file B.ma was not saved
do you want to save file A.ma ? yes
-> file A.ma was saved
Many Windows applications will interpret paths with two leading "/"s as UNC paths. I don't know if Maya is one of those, but try it out. If Maya can understand paths like "//servername/share/foo", then all you need to do is set up a SMB server named "linux", and the paths will work as they are. I would guess that this is actually what your client does, since the path "//linux" would not make sense in a Linux-only environment.
You can use environment variables to do this. Maya will expand environment vars present in a file path, you could use Maya.env to set them up properly for each platform.
What you are looking for is the dirmap mel command. It is completely non-intrusive to your files as you just define a mapping from your linux paths to windows and/or vice versa. Maya will internally apply the mapping to resolve the paths, without changing them when saving the file.
To setup dirmap, you need to run a MEL script which issues the respective commands on maya startup. UserSetup.mel could be one place to put it.
For more details, see the official documentation - this particular link points to maya 2012, the command is available in Maya 7.0 and earlier as well though:
http://download.autodesk.com/global/docs/maya2012/en_us/Commands/dirmap.html