I'm quite new to Python so bear with me, I downloaded a github project for Document Forgery Detection that works with 3.6 and buried within it is scipy.misc.imsave which is deprecated.
The call to scipy.misc.imsave only has one parameter but I can't find documentation for that call, only for two parameter methods.
So when I tried to upgrade to what I found recommended online, imageio I replaced the calls as so.
Before
scipy.misc.imsave(self.imageOutputDirectory + "MarkedImage")
After
imageio.imwrite(self.imageOutputDirectory + "MarkedImage")
Of course this doesn't work as it expects two params. The problem is I can't figure out what the original implementation was somehow passing to scipy to reference it, is it some inherited method in the class?
I have an OR problem and using an academic version of cplex library in the jupyter notebook by python 3.6.
When I am calling the following command I get an error:
command:
solution=mdl.solve(log_output=True)
error:
TypeError: can't pickle dict_keys objects
when I removed (log_output=True) everything works just fine, but I need the detailed output.
Since this is a crossed reference question, I would rather not repeat myself and confuse other people. The reason to ask here is that different scholars are attending these two reference webpages.
https://github.com/IBMDecisionOptimization/docplex-examples/issues/14
If I find my answer in stackoverflow I will share the solution procedure here and on github.
From the solution found in the external link: the problem is fixed in docplex ersion 2.10.150. Upgrading to that version fixes the problem.
As Daniel Junglas mentioned there were some inconsistencies between the two version of docplex toolbox and cplex 12.9 academic version I was using. A member of IBM team noticed the problem and updated the docplex version. And the lastest version up to date 07/08/2019 is here https://pypi.org/project/docplex/2.10.150/.
Many thanks to IBM Team.
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 have written a module for teaching Python. I'd like to make it difficult for the smarter ones to view the source code as a short-cut. Does not need to be fully secure - disabling the inspect module might be enough - if this is possible.
In case this is useful to anyone else using Python3 for class tests etc here's what I've ended up doing (with thanks to wbwlkr).
python3 -OO -m py_compile testmod.py creates a file __pycache__/testmod.cpython-34.pyo
Creating a symbolic link to this file named testmod.pyc means the code can't easily be inspected.
One other consideration is that sensitive local variables should be overwritten when not needed or they can be queried by locals()
What you are searching for is a solution to "obfuscate" the source code of your module.
You could compile your module to byte-code, as suggested here :
https://stackoverflow.com/a/7418341/8714367
In an IPython notebook, one would expect the following code to cause Raphael.js to load successfully into the global namespace.
from IPython.display import Javascript
raphael_url = "https://cdnjs.cloudflare.com/ajax/libs/raphael/2.1.0/raphael-min.js"
Javascript('alert(Raphael);', lib=[raphael_url])
However, it does not work in recent versions of IPython which use require.js. Turns out, Raphael.js, which IPython loads using jQuery.getScript(), recognizes the presence of require.js and as such does not insert itself into the global namespace. In fact, if one first runs javascript code removing the window.define object, Raphael no longer realizes require.js is present, and it inserts itself into the global namespace as I would like. In other words, the code above works after running the following:
Javascript('window.define = undefined;')
Thus, the only way I am able to get Raphael to load within a recent version of IPython notebook is to delete (or set aside) window.define.
Having identified the problem, I am not familiar enough with require.js to know what piece of software is acting against protocol. Is Raphael using a poor way of testing for the existence of require.js? Should IPython be using require.js directly instead of jQuery.getScript() when it loads user-provided javascript libraries? Or is there a way I as the user ought to be embracing require.js, which will give me the Raphael object without needing any special hacks? (If the answer to the last question is yes, is there a way I can also support older versions of IPython notebook, which do not use require.js?)
The first part of my answer won't please you, but the loading and requirement of javascript library in the IPython-notebook-webapp has not yet been solved, so for now I would suggest not to build to much on the assumption you can load library like that, and rely more on custom.js for now.
That being said, if raphael is not in global namespace require is smart enough to cache it, and give you reference to it. Then in the callback you can just assign to a global :
require(['raphael'], function( raph ){
window.raphael = raph;
})
Or something like that should do the trick.