Pruner Base Class¶
Module containing Pruner class.
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class
pruneabletree.pruner.Pruner(tree)[source]¶ Base class for decision tree pruners.
Warning: This class should not be used directly. Use derived classes instead.
Methods
is_leaf(node_id)Returns True if the given node is a leaf. leaf_prediction(node_id)Returns the class index of that the node with the given ID would predict. num_actual_nodes(tree)Returns the actual number of nodes in the given tree after pruning. num_instances(node_id[, y_idx])Returns the number of instances in a given node. num_leaves(tree)Returns the number of leaves. to_leaf(node_id, depths)Convert the node with the given ID to a leaf, pruning away its children. -
is_leaf(node_id)[source]¶ Returns True if the given node is a leaf.
Parameters: - node_id : int
The ID of the node in the tree
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leaf_prediction(node_id)[source]¶ Returns the class index of that the node with the given ID would predict.
Parameters: - node_id : int
The ID of the node in the tree
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static
num_actual_nodes(tree)[source]¶ Returns the actual number of nodes in the given tree after pruning.
This differs from the tree.node_count property, which contains the number of nodes before pruning. Updating this value would break other features since the underlying data structures still have their original sizes.
Parameters: - tree : Tree object
The underlying tree object of a DecisionTreeClassifier (e.g. clf.tree_).
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num_instances(node_id, y_idx=None)[source]¶ Returns the number of instances in a given node.
If a class index is given, only returns the number of instances belonging to that class.
Parameters: - node_id : int
The ID of the node in the tree
- y_idx : int, optional
The index of the class the instances should belong to. If provided, other classes are ignored.
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