In [11]:
#importing scikit-learn datasets package 
#and the RandonForestClassifier package
from sklearn import datasets
from sklearn.ensemble import RandomForestClassifier

iris = datasets.load_iris()
m = RandomForestClassifier()

In [12]:
#build a forest of trees from the training set (X, y)
m.fit(iris.data,iris.target)


Out[12]:
RandomForestClassifier(bootstrap=True, class_weight=None, criterion='gini',
            max_depth=None, max_features='auto', max_leaf_nodes=None,
            min_impurity_split=1e-07, min_samples_leaf=1,
            min_samples_split=2, min_weight_fraction_leaf=0.0,
            n_estimators=10, n_jobs=1, oob_score=False, random_state=None,
            verbose=0, warm_start=False)

In [13]:
#apply trees in the forest to X, return leaf indices
m.apply(iris.data)


Out[13]:
array([[ 2,  1,  1, ...,  1,  1,  1],
       [ 2,  1,  1, ...,  1,  1,  1],
       [ 2,  1,  1, ...,  1,  1,  1],
       ..., 
       [18, 14, 18, ..., 14, 22,  5],
       [18, 14, 18, ..., 14, 22,  5],
       [18, 12, 17, ..., 12, 22,  5]], dtype=int64)

In [10]:
#return the decision path in the forest
m.decision_path(iris.data)


Out[10]:
(<150x168 sparse matrix of type '<class 'numpy.int64'>'
 	with 5663 stored elements in Compressed Sparse Row format>,
 array([  0,  19,  44,  65,  82,  93, 102, 119, 134, 153, 168], dtype=int32))

In [14]:
#fit to data and transform the result
m.fit_transform(iris.data,iris.target)


C:\Users\priyu\Anaconda3\lib\site-packages\sklearn\utils\deprecation.py:70: DeprecationWarning: Function transform is deprecated; Support to use estimators as feature selectors will be removed in version 0.19. Use SelectFromModel instead.
  warnings.warn(msg, category=DeprecationWarning)
Out[14]:
array([[ 1.4,  0.2],
       [ 1.4,  0.2],
       [ 1.3,  0.2],
       [ 1.5,  0.2],
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       [ 5.2,  2. ],
       [ 5.4,  2.3],
       [ 5.1,  1.8]])

In [7]:
#get parameters for the estimator
m.get_params()


Out[7]:
{'bootstrap': True,
 'class_weight': None,
 'criterion': 'gini',
 'max_depth': None,
 'max_features': 'auto',
 'max_leaf_nodes': None,
 'min_impurity_split': 1e-07,
 'min_samples_leaf': 1,
 'min_samples_split': 2,
 'min_weight_fraction_leaf': 0.0,
 'n_estimators': 10,
 'n_jobs': 1,
 'oob_score': False,
 'random_state': None,
 'verbose': 0,
 'warm_start': False}

In [8]:
#predict class for X
m.predict(iris.data)


Out[8]:
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
       1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
       2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
       2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2])

In [9]:
#predict class log probabilities for X
m.predict_log_proba(iris.data)


/home/harish/anaconda3/lib/python3.5/site-packages/sklearn/ensemble/forest.py:628: RuntimeWarning: divide by zero encountered in log
  return np.log(proba)
Out[9]:
array([[ 0.        ,        -inf,        -inf],
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In [10]:
#predict class probabilities for X
m.predict_proba(iris.data)


Out[10]:
array([[ 1. ,  0. ,  0. ],
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In [15]:
#returns the mean accuracy on the given test data and labels
m.score(iris.data,iris.target)


Out[15]:
0.99333333333333329