Python Weka API-Data classification error

[bhanu prakash]

When I am trying trying to apply classification on the data set with we are encountering error at cls.build_classifier(data).

please help us our.

from weka.classifiers import Classifier
import weka.core.jvm as jvm
jvm.start(system_cp=True, packages=True)
import weka.core.converters as converters
data = converters.load_any_file("KDDTrain.csv")
data.class_is_last()
#print(data)
cls = Classifier(classname="weka.classifiers.trees.J48", options=["-C", "0.3"])
cls.build_classifier(data)

for index, inst in enumerate(data):
    pred = cls.classify_instance(inst)
    dist = cls.distribution_for_instance(inst)

print(str(index+1) + ": label index=" + str(pred) + ", class distribution=" + str(dist))

error :

C:\Users\bhanu\PycharmProjects\main_project\venv\Scripts\python.exe C:/Users/bhanu/PycharmProjects/main_project/test_class.py

DEBUG:weka.core.jvm:Adding bundled jars

DEBUG:weka.core.jvm:Adding system classpath

DEBUG:weka.core.jvm:Classpath=['C:\\Users\\bhanu\\PycharmProjects\\main_project\\venv\\lib\\site-packages\\javabridge\\jars\\rhino-1.7R4.jar', 'C:\\Users\\bhanu\\PycharmProjects\\main_project\\venv\\lib\\site-packages\\javabridge\\jars\\runnablequeue.jar', 'C:\\Users\\bhanu\\PycharmProjects\\main_project\\venv\\lib\\site-packages\\javabridge\\jars\\cpython.jar', 'C:\\Users\\bhanu\\PycharmProjects\\main_project\\venv\\lib\\site-packages\\weka\\lib\\python-weka-wrapper.jar', 'C:\\Users\\bhanu\\PycharmProjects\\main_project\\venv\\lib\\site-packages\\weka\\lib\\weka.jar']

DEBUG:weka.core.jvm:MaxHeapSize=default

DEBUG:weka.core.jvm:Package support enabled

DEBUG:javabridge.jutil:Creating JVM object

DEBUG:javabridge.jutil:Signalling caller

weka.core.UnsupportedAttributeTypeException: weka.classifiers.trees.J48: Cannot handle numeric class!

weka.core.Capabilities.test(Capabilities.java:1067)

weka.core.Capabilities.test(Capabilities.java:1256)

weka.core.Capabilities.test(Capabilities.java:1138)

weka.core.Capabilities.testWithFail(Capabilities.java:1468)

weka.classifiers.trees.J48.buildClassifier(J48.java:277)

at weka.core.Capabilities.test(Capabilities.java:1067)

at weka.core.Capabilities.test(Capabilities.java:1256)

at weka.core.Capabilities.test(Capabilities.java:1138)

at weka.core.Capabilities.testWithFail(Capabilities.java:1468)

at weka.classifiers.trees.J48.buildClassifier(J48.java:277)

Traceback (most recent call last):

  File "C:/Users/bhanu/PycharmProjects/main_project/test_class.py", line 10, in <module>

    cls.build_classifier(data)

  File "C:\Users\bhanu\PycharmProjects\main_project\venv\lib\site-packages\weka\classifiers.py", line 83, in build_classifier

    javabridge.call(self.jobject, "buildClassifier", "(Lweka/core/Instances;)V", data.jobject)

  File "C:\Users\bhanu\PycharmProjects\main_project\venv\lib\site-packages\javabridge\jutil.py", line 887, in call

    result = fn(*nice_args)

  File "C:\Users\bhanu\PycharmProjects\main_project\venv\lib\site-packages\javabridge\jutil.py", line 854, in fn

    raise JavaException(x)

javabridge.jutil.JavaException: weka.classifiers.trees.J48: Cannot handle numeric class!

Regards

Bhanuprakash Vattikuti

+91 8977569778

bhanu...@gmail.com 

[Peter Reutemann]

J48 is a classification algorithm (categorical or nominal class
attribute), not to be used for regression (numeric class attribute).

I'm not familiar with your dataset, but if the last attribute is
actually a categorical one (ie with categories like 1, 2, 3, etc),
then you need to convert that attribute for Weka.
You can use the "NumericToNominal" for this, with the range being the
last attribute:
http://weka.sourceforge.net/doc.dev/weka/filters/unsupervised/attribute/NumericToNominal.html

You might have to apply the filter before you're setting the class
attribute with "data.class_is_last()".

Cheers, Peter
--
Peter Reutemann
Dept. of Computer Science
University of Waikato, NZ
+64 (7) 858-5174
http://www.cms.waikato.ac.nz/~fracpete/
http://www.data-mining.co.nz/

[Marcelinus David]

Peter, i want to ask something, when i try import :

import weka.core.jvm as jvm
from weka.core.converters import Loader

I always get this error:

Traceback (most recent call last)

:

  File "C:\Users\M\Anaconda3\lib\site-packages\IPython\core\interactiveshell.py", line 2961, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)

  File "<ipython-input-3-77c39c862f2f>", line 2, in <module>
    from weka.classifiers import Classifier

  File "C:\Users\M\Anaconda3\lib\site-packages\weka\classifiers.py", line 2169
    except Exception, e:
                    ^
SyntaxError: invalid syntax

and if i import:
from weka.core.converters import Loader

I always get this error:

Traceback (most recent call last)

:

  File "C:\Users\M\Anaconda3\lib\site-packages\IPython\core\interactiveshell.py", line 2961, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)

  File "<ipython-input-4-cec7ec6ac826>", line 1, in <module>
    from weka.core.converters import Loader

  File "C:\Users\M\Anaconda3\lib\site-packages\weka\core\converters.py", line 18, in <module>
    from weka.core.classes import OptionHandler

  File "C:\Users\M\Anaconda3\lib\site-packages\weka\core\classes.py", line 2085
    except Exception, e:
                    ^
SyntaxError: invalid syntax


These errors always occur while i am using pyhton 3.7. You know why ?

[Peter Reutemann]

> Peter, i want to ask something, when i try import :
> import weka.core.jvm as jvm
> from weka.core.converters import Loader
>
> I always get this error:
>
> Traceback (most recent call last):
>
> File "C:\Users\M\Anaconda3\lib\site-packages\IPython\core\interactiveshell.py", line 2961, in run_code
> exec(code_obj, self.user_global_ns, self.user_ns)
>
> File "<ipython-input-3-77c39c862f2f>", line 2, in <module>
> from weka.classifiers import Classifier
>
> File "C:\Users\M\Anaconda3\lib\site-packages\weka\classifiers.py", line 2169
> except Exception, e:
> ^
> SyntaxError: invalid syntax

Looks like you're using the Python 2.7 version of the library
("python-weka-wrapper") instead of the Python 3 version
("python-weka-wrapper3").

[Marcelinus David]

OMG, i am using python-weka-wrapper. Thank you the problem solved.