Is it possible to set up a custom section in the pipfile?
By default I see only [packages] and [dev-packages], but I have extra dependencies for some environment. So I want to install packages and for example [tests] but not [dev-packages].
E.G.:
pipenv install --tests
# or
pipenv install --my-custom-section
Before that I used requirements.txt, requirements-dev.txt, requirements-integration.txt. Is there any good way to implement it with pipenv?
Let's look into documentation
If we look in Pipfile. The Concept:
Pipfile will be superior to requirements.txt file in a number of ways:
...
Existing requirements files tend to proliferate into multiple files - e.g. dev-requirements.txt, test-requirements.txt, etc. - but a Pipfile will allow seamlessly specifying groups of dependencies in one place. * This will be surfaced as only two built-in groups (default & development). (see note below)
Note
Custom groups may be added in the future. Remember, it is easier to add features in the future than it is to remove them. The Composer community has been successful with only default and development as group options for many years. This model is being followed.
Answer
It's not possible now although it was designed with idea of such possibility.
Maybe it will be possible in future.
What is the best way to call java from python?
(jython and RPC are not an option for me).
I've heard of JCC: http://pypi.python.org/pypi/JCC/1.9
a C++ code generator for calling Java from C++/Python
But this requires compiling every possible call; I would prefer another solution.
I've hear about JPype: http://jpype.sourceforge.net/
tutorial: http://www.slideshare.net/onyame/mixing-python-and-java
import jpype
jpype.startJVM(path to jvm.dll, "-ea")
javaPackage = jpype.JPackage("JavaPackageName")
javaClass = javaPackage.JavaClassName
javaObject = javaClass()
javaObject.JavaMethodName()
jpype.shutdownJVM()
This looks like what I need.
However, the last release is from Jan 2009 and I see people failing to compile JPype.
Is JPype a dead project?
Are there any other alternatives?
You could also use Py4J. There is an example on the frontpage and lots of documentation, but essentially, you just call Java methods from your python code as if they were python methods:
from py4j.java_gateway import JavaGateway
gateway = JavaGateway() # connect to the JVM
java_object = gateway.jvm.mypackage.MyClass() # invoke constructor
other_object = java_object.doThat()
other_object.doThis(1,'abc')
gateway.jvm.java.lang.System.out.println('Hello World!') # call a static method
As opposed to Jython, one part of Py4J runs in the Python VM so it is always "up to date" with the latest version of Python and you can use libraries that do not run well on Jython (e.g., lxml). The other part runs in the Java VM you want to call.
The communication is done through sockets instead of JNI and Py4J has its own protocol (to optimize certain cases, to manage memory, etc.)
Disclaimer: I am the author of Py4J
Here is my summary of this problem: 5 Ways of Calling Java from Python
http://baojie.org/blog/2014/06/16/call-java-from-python/ (cached)
Short answer: Jpype works pretty well and is proven in many projects (such as python-boilerpipe), but Pyjnius is faster and simpler than JPype
I have tried Pyjnius/Jnius, JCC, javabridge, Jpype and Py4j.
Py4j is a bit hard to use, as you need to start a gateway, adding another layer of fragility.
Pyjnius docs and Github.
From the github page:
A Python module to access Java classes as Python classes using JNI.
PyJNIus is a "Work In Progress".
Quick overview
>>> from jnius import autoclass
>>> autoclass('java.lang.System').out.println('Hello world')
Hello world
>>> Stack = autoclass('java.util.Stack')
>>> stack = Stack()
>>> stack.push('hello')
>>> stack.push('world')
>>> print stack.pop()
world
>>> print stack.pop()
hello
If you're in Python 3, there's a fork of JPype called JPype1-py3
pip install JPype1-py3
This works for me on OSX / Python 3.4.3. (You may need to export JAVA_HOME=/Library/Java/JavaVirtualMachines/your-java-version)
from jpype import *
startJVM(getDefaultJVMPath(), "-ea")
java.lang.System.out.println("hello world")
shutdownJVM()
I'm on OSX 10.10.2, and succeeded in using JPype.
Ran into installation problems with Jnius (others have too), Javabridge installed but gave mysterious errors when I tried to use it, PyJ4 has this inconvenience of having to start a Gateway server in Java first, JCC wouldn't install. Finally, JPype ended up working. There's a maintained fork of JPype on Github. It has the major advantages that (a) it installs properly and (b) it can very efficiently convert java arrays to numpy array (np_arr = java_arr[:])
The installation process was:
git clone https://github.com/originell/jpype.git
cd jpype
python setup.py install
And you should be able to import jpype
The following demo worked:
import jpype as jp
jp.startJVM(jp.getDefaultJVMPath(), "-ea")
jp.java.lang.System.out.println("hello world")
jp.shutdownJVM()
When I tried calling my own java code, I had to first compile (javac ./blah/HelloWorldJPype.java), and I had to change the JVM path from the default (otherwise you'll get inexplicable "class not found" errors). For me, this meant changing the startJVM command to:
jp.startJVM('/Library/Java/JavaVirtualMachines/jdk1.7.0_79.jdk/Contents/MacOS/libjli.dylib', "-ea")
c = jp.JClass('blah.HelloWorldJPype')
# Where my java class file is in ./blah/HelloWorldJPype.class
...
I've been integrating a lot of stuff into Python lately, including Java. The most robust method I've found is to use IKVM and a C# wrapper.
IKVM has a neat little application that allows you to take any Java JAR, and convert it directly to .Net DLL. It simply translates the JVM bytecode to CLR bytecode. See http://sourceforge.net/p/ikvm/wiki/Ikvmc/ for details.
The converted library behaves just like a native C# library, and you can use it without needing the JVM. You can then create a C# DLL wrapper project, and add a reference to the converted DLL.
You can now create some wrapper stubs that call the methods that you want to expose, and mark those methods as DllEport. See https://stackoverflow.com/a/29854281/1977538 for details.
The wrapper DLL acts just like a native C library, with the exported methods looking just like exported C methods. You can connect to them using ctype as usual.
I've tried it with Python 2.7, but it should work with 3.0 as well. Works on Windows and the Linuxes
If you happen to use C#, then this is probably the best approach to try when integrating almost anything into python.
I'm just beginning to use JPype 0.5.4.2 (july 2011) and it looks like it's working nicely...
I'm on Xubuntu 10.04
I'm assuming that if you can get from C++ to Java then you are all set. I've seen a product of the kind you mention work well. As it happens the one we used was CodeMesh. I'm not specifically endorsing this vendor, or making any statement about their product's relative quality, but I have seen it work in quite a high volume scenario.
I would say generally that if at all possible I would recommend keeping away from direct integration via JNI if you can. Some simple REST service approach, or queue-based architecture will tend to be simpler to develop and diagnose. You can get quite decent perfomance if you use such decoupled technologies carefully.
Through my own experience trying to run some java code from within python in a manner similar to how python code runs within java code in python, I was unable to find a straightforward methodology.
My solution to my problem was by running this java code as BeanShell scripts by calling the BeanShell interpreter as a shell command from within my python code after editing the java code in a temporary file with the appropriate packages and variables.
If what I am talking about is helpful in any manner, I am glad to help you share more details of my solutions.
I am using Python3.4. I have installed a certain "itunespy" library from GitHub with pip, to work with iTunes API.
(https://github.com/spaceisstrange/itunespy)
I can now access it from console by
import itunespy
Except the library is only searching the US store through iTunes Api, whereas I need to access the UK store. I looked into the code and found I only need to change two lines to fix my problem.
Please can you tell me how I can access and change the source code of an already installed library.
Thank you.
Fork the repository
Clone the forked repository
Make changes and push to your remote (origin, usually)
You may pip install from your fork
I took a look at source code, and:
a) you may obviously change your source code in locally-copied file
b) you may patch these constants in run-time, like adding this type of code to your main:
import itunespy
itunespy.base_search_url = "NEW_VALUE"
itunespy.base_lookup_url = "NEW_VALUE"
c) library API seems to provide country keyword argument, so you do not have to do any of these hacks mentioned above. Simply do:
itunespy.search_track('something', country='UK')
With this keyword argument, searches should work as expected without any modifications of source code.
you really want to change the sourcecode?
How about just change your implementation?
inherit from the class
override/overload their methods with your own
work with your inherited class and their methods
pro: if there are changes in the original library you will take them with you when you update (secure-patches etc.) but your overridden/overloaded methods are still the one you use.
otherwise if you really want to change the source code, take a branch from github and change the sourcecode as you need it like mentioned by dolftax
I am trying to run the PumpingSystem Example in the openmodelica Fluid library using the nightly build 1.9.1+dev (r21018). Unfortunately the simulation crashes saying it failed to solve NLS at initialization.
I tried to modify the model either by creating a new one extending it (which only permits the modification of the parameters but not the structure, I understand that this is probably what extension means) or by copying the text view of the model to a new file, but then OMEdit crashes.
Will you please advise how I can create a copy that I can modify?
Thank you.
PS: I am running this on Linux, the Windows version seems to translate all libraries,creates an infinite amount of translation errors "expected package to have within ; but got ..." and then terminates with a translation error "C:/OpenModelica1.9.1Nightly/lib/omlibrary/Modelica 3.2.1/Blocks/Continuous/Internal/Filter/Utilities/normalizationFactor.mo:14:3-42:27] Error: An element with name normalizationResidue is already declared in this scope."
You can not modify the system libraries. You can only extend them.
Creating a copy of the model is currently not supported. You can follow this ticket https://trac.openmodelica.org/OpenModelica/ticket/2190
If you just copy paste the text, as you already did, you need to manually update the relative paths used in the model.
I have a dynamic library that changes name across major versions i.e. version 3 was named lib3 and version 4 is named lib4, and so on.
I need to provide a shim lib3 that will allow an old application to use the new library in a transparent way, and most of the exported functions did not change across versions, so a forwarding DLL looks pretty good for the task on Windows.
Is there something equivalent on Linux/Unix?
The Linux equlivalent is rather easy. You can just use a symbolic link. For example, lib4 is the new library version, then you can create the following symbolic link:
ln -s lib4 lib3
Now, every time a program will need lib3 will automatically load lib4 as long as the interface
exported by the new version is equal to the old version, the program will not notice the difference.
I hope this helps. Let me know if you need more info.