'Length of feature names doesn't match with number of features' error while plotting decision tree using Graphviz

Question

I am trying to visualize a decision tree using graphviz and while trying to plot the decision tree I am getting the below error :

~\AppData\Local\Continuum\anaconda3\lib\site-packages\sklearn\tree\export.py in export_graphviz(decision_tree, out_file, max_depth, feature_names, class_names, label, filled, leaves_parallel, impurity, node_ids, proportion, rotate, rounded, special_characters, precision)
    427                                  "does not match number of features, %d"
    428                                  % (len(feature_names),
--> 429                                     decision_tree.n_features_))
    430 
    431         # The depth of each node for plotting with 'leaf' option

ValueError: Length of feature_names, 225 does not match number of features, 

208

My code

dt=DecisionTreeClassifier(class_weight="balanced", min_samples_leaf=30)
fit_decision=dt.fit(X_train_res,y_train_res)
from graphviz import Source
from sklearn import tree
Source( tree.export_graphviz(fit_decision, out_file=None, feature_names=data.columns))

Can you tell me what went wrong?

Answer 1

Your data.columns contains names of all the features+label since it is not divided into X_train_res and y_train_res. You need to pass the feature names in in X_train_res instead of data.columns to get the exact features else it will include the labels as well. I am assuming that X_train and y_train are derived from data in this case.