For my gae python project, I'd like to import an external library named 'vobject'. What's the correct way to import it in my .py files?
The project's readme says that in order to install it, you need to run
python setup.py install
Additionally, vobject requires the 'dateutil' package.
Since this is going to run on GAE, I thought I should copy both libs over into my project instead of running the install script to make use of it in my code.
But I'm getting a bunch of import errors and I'm not sure what the correct convention is for external gae/python libs.
utc = dateutil.tz.tzutc()
## error produced:
File "myGaeProject/external/vobject/icalendar.py", line 47, in <module>
NameError: name 'dateutil' is not defined
Because of the way I've structured my project, I changed icalendar.py's import structure from:
import dateutil.rrule
import dateutil.tz
to:
import external.dateutil.rrule
import external.dateutil.tz
I also tried:
from external.dateutil import *
What's the correct import mechanism for a project structured like so:
-myGaeProject
--external
----__init__.py
----dateutil
------__init__.py
------tz.py
------rrule.py
------[more dateutil files]
----vobject
------__init__.py
------base.py
------icalendar.py
--handlers
------__init__.py
------mainHandler.py
Don't modify the library. If you want to put all your libraries in external, you need to add external to your python path before you attempt to import libraries from there:
import os
import sys
sys.path.append(os.path.join(os.path.dirname(__file__), 'external'))
import some_external_library
You can't do from external import dateutil if external is missing an __init__.py file.
The good way is to use zipimport, you can check the project jaikuengine they are a lot of good things about that.
http://code.google.com/p/jaikuengine/source/browse/trunk/build.py
In Jaiku, all external libs are stocked in the directory vendor but if you see the app.yaml, all files in vendor are skipped.
Jaiku uses a script to build a zip of each libs in vendor and put it to the root of the project before the deployment or when the dev_server is launched.
With that, you don't need to fix the path of your libs.
EDIT an example to load all zipped archives
Largely inspired from jaikuengine:
def load_zipped(path='.'):
for x in os.listdir(path):
if x.endswith('.zip'):
if not any([y.endswith(x) for y in sys.path]):
sys.path.append(os.path.abspath('%s/%s') % (path, x))
Related
I am working on a project based on Python 2.7 and I am trying to import a module which is in a package folder that contains __init__.py and the file that I want to import called package1.py, but I am unable to do so. This is my folder structure: main_project/Tools/common/package1.py
Note that my project files are in the folder main_project. So, I am trying to call the package1.py by using an import statement in my script:
from Tools.common.package1 import variable
But I am getting an ImportError: No module named Tools.common.package1.
What is the solution to solving this error as I want to use the package feature for my project?
Maybe use the solution i found here :
# some_file.py
import sys
# insert at 1, 0 is the script path (or '' in REPL)
sys.path.insert(1, '/path/to/application/app/folder')
import file
or verify your module has a __init__.py
Importing files from different folder
Ok I have found the answer. I also had to insert an init.py in the folder Tools as well. Initially I only inserted init.py in common but not in Tools as we should also make Tools a package if we want to access common
I have a few seperate pythone file and I am using them to import another py file. Modules that trying to import them are in seperate folder I code sample is below
from tez.library.image_crop import ImageCrop
from tez.library.image_process import ImageProcess
from tez.library.image_features import ImageFeatures
from tez.const.application_const import ApplicationConst
from tez.library.file_operation import FileOperation
this code is in where I want to start the py file using commond line as "python samples1.py" and thrown an error as below
Traceback (most recent call last): File "samples1.py", line 1, in
from tez.library.image_crop import ImageCrop ModuleNotFoundError: No module named 'tez'
folder structure :
.tez
-- library
---- image_crop.py
---- image_process.py
---- image_features.py
--src
---- samples1.py
Python version : 3.8
Pip : 20.0.2
Windows 10 Pro 1909
If you are building a package called tez (and since you tried to import it I think you are). Then everything with tez needs to refer to itself locally. All the files in the tez package need to refer to each other with the "." and ".." imports.
In samples1.py:
from ..library.image_crop import <something>
EDIT:
It sounds like you are misunderstanding how python imports things. When you run "import X" in a python script, then python looks for a package named X under sys.path. You can append to sys.path at the top of your script if you have a custom package to look for.
import sys
sys.path.append(<directory of tez>)
import tez
However, it is strongly recommended that you should not be importing from a file that is under the directory structure of the package name. If "examples" is a directory of examples that use the package "tez" then "examples" should be located outside the package "tez". If "examples" is inside the package "tez", then "examples" should be doing local imports "with-in" the package.
Getting a handle on package use can be tricky.
sample.py can't see above of src folder, but you can tell Python to do this.:
import sys
import os
tez = os.path.dirname(os.path.dirname(__file__))
# __file__ is path of our file (samples.py)
# dirname of __file__ is "src" in our state
# dirname of "src" is "tez" in our state
sys.path.append(tez) # append tez to sys.path, python will look at here when you try import something
import library.image_crop # dont write "tez"
But this is not a very good design I think.
I read a book to learn python programming, it showed the code :
import media
So I downloaded gwpy-code.zip from the link http://pragprog.com/titles/gwpy/source_code and installed PyGraphics-2.0.win32.exe . In the path C:\Python27\Lib\site-packages\pygraphics there really was media.py ! But why import media didn't work ?
(ps: I also tried this C:\Python27\Scripts\easy_install nose in the DOS box, still not work...)
Best Regards :)
Try:
from pygraphics import media
If you're not familiar with importing modules in Python yet, a brief primer might be useful.
>>> import sys
>>> print sys.path
If you try the code above, you will see a bunch of directories on your system path. C:\Python27\Lib\site-packages\ should be one of these.
To import a file located on your system path, you can use import filename (for filename.py). If the file lies in a subdirectory, e.g. dir1/dir2/filename.py, it can be imported using import dir1.dir2.filename.
Note: A directory acts as a 'package' if it contains a file called __init__.py. A file that can be imported is called a 'module'.
You need to do:
from pygraphics import media
The reason is that Python looks in the site-packages directory for packages. The file media.py is within the folder (and therefore the package) pygraphics, so you can't get to it directly.
Before you import media, you must import ampy.
You might have to say
from pygraphics import media
Google App engine documentation states that it is possible to upload and use third party libraries provided they written in pure Python.
What are the steps I need to take to do this?
What I did is created a file called fix_path.py in my root directory that looks like this:
import os
import sys
import jinja2
# path to lib direcotory
sys.path.insert(0, os.path.join(os.path.dirname(__file__), 'lib'))
Then I created a lib directory, and drop the module in there.
For example, I use WTForms. My file structure looks like this.
lib
wtforms
fix_path.py
somefile.py
when I am ready to call it from my somefile script
import fix_path # has to be first.
import wtforms
here is this example in my github source. checkout fix_path.py for setup and views.py for usage.
Well I tried the same with following steps.
created a directory(lib) with init file i.e lib/__init__.py in my project root.
created my module (mymodule.py), and defined a function i.e.
def myfunc():
return "mycustomfunction"
imported mymodule in my main.py
from lib import mymodule
I could use the returned value from myfunc() and could pass that as a template value to my jinja2 template
Similarly, if we follow what #rjz also pointed out in the first answer, if the 3rd Party library is just a module then we can keep that in libs with an init file and it can be imported with an import statement ( point 3) . If the 3rd party library is a package then we can keep it in the project root and import it again with an import statement as this one in the main.py:
from thirdpartypackage import *
For my Python application, I have the following directories structure:
\myapp
\myapp\utils\
\myapp\utils\GChartWrapper\
\myapp\model\
\myapp\view\
\myapp\controller\
One of my class in \myapp\view\ must import a class called GChartWrapper. However, I am getting an import error...
myview.py
from myapp.utils.GChartWrapper import *
Here is the error:
<type 'exceptions.ImportError'>: No module named GChartWrapper.GChart
args = ('No module named GChartWrapper.GChart',)
message = 'No module named GChartWrapper.GChart'
What am I doing wrong? I really have a hard time to import modules/classes in Python...
The __init__.py file of the GChartWrapper package expects the GChartWrapper package on PYTHONPATH. You can tell by the first line:
from GChartWrapper.GChart import *
Is it necessary to have the GChartWrapper included package in your package directory structure?
If so, then one thing you could do is adding the path where the package resides to sys.path at run time. I take it myview.py is in the myapp\view directory? Then you could do this before importing GChartWrapper:
import sys
import os
sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'utils')))
If it is not necessary to have it in your directory structure, it could be easier to have it installed at the conventional location. You can do that by running the setup.py script that's included in the GChartWrapper source distribution.
You don't import modules and packages from arbritary paths. Instead, in python you use packages and absolute imports. That'll avoid all future problems.
Example:
create the following files:
MyApp\myapp\__init__.py
MyApp\myapp\utils\__init__.py
MyApp\myapp\utils\charts.py
MyApp\myapp\model\__init__.py
MyApp\myapp\view\__init__.py
MyApp\myapp\controller\__init__.py
MyApp\run.py
MyApp\setup.py
MyApp\README
The files should be empty except for those:
MyApp\myapp\utils\charts.py:
class GChartWrapper(object):
def __init__(self):
print "DEBUG: An instance of GChartWrapper is being created!"
MyApp\myapp\view\__init__.py:
from myapp.utils.charts import GChartWrapper
def start():
c = GChartWrapper() # creating instance of the class
MyApp\run.py:
from myapp.view import start
start()
That's all! When you run your entry point (run.py) it calls a function on the view, and that creates an instance of the GChartWrapper class. Using this structure you can import anything anywhere and use it.
To complement, in MyApp\setup.py you write an installation program for the MyApp\myapp package. Use distutils to write it:
from distutils.core import setup
setup(name='MyApp',
version='1.0',
description='My Beautiful Application',
author='Martin',
author_email='martin#xxxxxxx.com',
url='http://stackoverflow.com/questions/1003843/',
packages=['myapp'],
scripts=['run.py']
)
That is enough. Now when people download the MyApp folder, they can just install it using setup.py and run it using run.py. Distutils can generate packages in a number of formats including windows installable .EXE
It's the standard way of distributing python packages/applications.
You can change the path where python looks for files.
At the top of your source file, add:
import sys
sys.path.append("..")
Or alternatively change the environment variable:
export PYTHONPATH=..
Or starting in python 2.5 (again assuming myview is in myapp\view:
from __future__ import absolute_import
from ..utils.GChartWrapper import *
See: http://docs.python.org/whatsnew/2.5.html#pep-328-absolute-and-relative-imports
GChartWrapper is also available from PyPI so you can use easy_install or pip to install the module:
sudo pip install GChartWrapper==0.9
It will then be automatically added to your PYTHONPATH and then you can remove it from your /myapp/utils directory. If you can't use sudo, look at using virtualenv (and virtualenvwrapper).