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Questions tagged [j48]

J48 is an open source Java implementation of the C4.5 algorithm in the Weka data mining tool.

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Interpreting results using J48 for a divided attribute of interest in x levels (WEKA)

I'm new to data mining and Weka. I built a classifier with J48 in Weka using the GUI, with J48 (training set) for an attribute of interest in five levels. I have to evaluate the precision of the model, but I don't know very well how to do it! Some…
fina
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Plot decision tree based on strings with J48 algorithm for prediction

I'm trying to plot J48 decision tree based on string values attributes and predict the target variable(categorical), I have seen many examples plotting decision tree based on numerical values but i haven't come across based on strings. Here is…
louis
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Weka J48 Gets stuck on Building Model on Training Data

I'm trying to use Weka to look at my data sets. When I load my data set in, and I got to classify and I choose J48 and click start it will being normally, my bird in the bottom right hand corner will go back and forth and there will be a x 1 next…
Fletchy
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Weka Decision Tree getting too big (out of memory)

For classification I used Weka's J48 decision tree to build a model on several nominal attributes. Now there is more data for classification (5 nonimal attributes) but each attribute has 3000 different values. I used J48 with pruning but it ran out…
P. Moe
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Test instances always classified in to the the same class

I have written a java program that build a J48 classifier using training set. Then I pass a test instance to the classifier to predict the unknown class. But each and every test instance classified in to first element of the class attribute.…
dennypanther
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Is there way to read a J48 Pruned Tree from a text file?

Given a text file with the following contents (say weather.txt): outlook = sunny | humidity <= 75: yes (2.0) | humidity > 75: no (3.0) outlook = overcast: yes (4.0) outlook = rainy | windy = TRUE: no (2.0) | windy = FALSE: yes (3.0) Is…
Ankita Mehta
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Weka: Predicted values

In Weka, I am using the J48 classifier to make predictions. However, I notice that in the prediction output the instance order (of both actual and predicted instance values) does not correspond to the original order (ie. rows) of the dataset that I…
AppleCinnamon
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Classification rate Weka Java API

I would like to get the classification rate for a tree constructed using J48. DataSource source = new DataSource(Path); Instances data = source.getDataSet(); J48 tree = tree.buildClassifier(data); I know it has something to do with public double…
Zahzah
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WEKA using class values to solve decision tree?

I am brand new to WEKA and ML, so please excuse my ignorance with the following. I've wasted several hours trying to figure it out, so hopefully someone could point me in the right direction: I am trying to run a J48 decision tree on data for…
trock2000
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Incorrectly classified instances in the tree do not match confusion matrix

The sum of the incorrect classification (see tree) in all rules is 2097 (which is from 895+700+428+74) . But the confusion matrix is 2121 (which is from 1999+122). Can someone explain the discrepancy? How come the numbers are different?
Chrizelle
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Generating a Decision Tree that Perfectly Models the Training Set?

I have my data set which are my rules, and I want to generate a decision tree that at least has 100% accuracy at classifying my rules, but I can never get 100%. I set minNumObjs to 1 and made it unpruned but I only get 84% correctly classified…
jmasterx
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Getting properties values of J48

Following my question I would like to know what should I add in order to get the value of the node and to concatenate it to its name. I have a J48 decision tree: library(RWeka) data(iris) res = J48(Species ~., data = iris) > res J48 pruned…
Avi
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Understanding partykit graph out of j48 in R

I've made an analysis of a dataset i have consisting on 266 istances and about 100 indicators on that using j48 tree in R. I'm not the most skilled in machine learning, anyway i managed to get the j48 tree in both Weka and R. In the latter i found…
Ciochi
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WEKA J48 setting the root manually

Is there any ways to force setting root of a decision tree in j48 using weka? Because I want to see clearly if the root is changed, what will be the changes caused to the tree.
Hon Lun Chan
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Visualize j48 tree weka

I want to visualize my tree in a nicer layout GraphViz, but for some reason it doesn't show the tree at all even though it does show in the default layout.
A.J
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