Weka Python包装器加载器

Question

I've installed weka python wrapper on Mc Os X 10.9.4. And I tried running the sample code:

import weka.core.jvm as jvm
jvm.start()

from weka.core.converters import Loader
l = Loader("weka.core.converters.ArffLoader")
d = l.load_file("X.arff")

d.set_class_index(d.num_attributes() - 1)
print(d)

and I receive the following error:

Failed to get class weka/core/converters/ArffLoader
Exception in thread "Thread-2" java.lang.NoClassDefFoundError: weka/core/converters/ArffLoader
Failed to instantiate weka.core.converters.ArffLoader/weka/core/converters/ArffLoader: weka/core/converters/ArffLoader
Caused by: java.lang.ClassNotFoundException: weka.core.converters.ArffLoader
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
Traceback (most recent call last):
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 2883, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-5-d835d9d560d2>", line 2, in <module>
    l = Loader("weka.core.converters.ArffLoader")
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/python_weka_wrapper-0.1.10-py2.7.egg/weka/core/converters.py", line 40, in __init__
    self.enforce_type(jobject, "weka.core.converters.Loader")
  File "/Users/hani/Library/Enthought/Canopy_64bit/User/lib/python2.7/site-packages/python_weka_wrapper-0.1.10-py2.7.egg/weka/core/classes.py", line 113, in enforce_type
    raise TypeError("Object does not implement or subclass " + intf_or_class + "!")
TypeError: Object does not implement or subclass weka.core.converters.Loader!

After some tinkering I realized that setting the working directory to the python-weka-wrapper folder using os.chdir remedies the problem in some environments but not all of them (eg pycharm is not fixed using this trick). Any ideas how I can fix this issue?

Answer 1

Apparently, calling jvm with the paths to weka jar files would solve the problem:

jvm.start(class_path=['/some/where/python-weka-wrapper.jar', 
'/some/where/weka.jar'])

Thanks to Peter Reutemann for this reply.