edu.stanford.nlp.ie.pcfg
Class TreeUtil

java.lang.Object
  |
  +--edu.stanford.nlp.ie.pcfg.TreeUtil

public class TreeUtil

extends Object

This class contains many utility functions for performing common tree operations. It's very possible that much of this functionality overlaps with that provided by existing JavaNLP code.

Field Summary

static String

startSymbol this symbol marks the top of a tree.

Constructor Summary

TreeUtil()

Method Summary

static Tree	AddTop(Tree tree) Adds a new node (with label == startSymbol) to the root of the tree.
static void	Clean(Tree tree, boolean includeTags, boolean includeHead) Removes tag and head information from all labels in a tree.
static void	CleanLabels(Tree tree) Strips tag information from all labels in a tree Use Clean(Tree tree, boolean includeTags, boolean includeHead) instead!
static void	CleanLeaves(Tree tree) Removes tag information from all the nodes in a tree
static void	CleanTop(Tree tree) Removes tag information from the top node in a tree.
static void	CopyTags(Tree fromTree, Tree toTree) copy label tags from fromTree to toTree.
static void	DoSlyTricks(Tree tree)
static Tree	GetCopy(Tree tree) Makes a deep copy.
static Tree	GetHeadedCopy(Tree tree) Gets a copy of tree, including some lexical head information.
static Tree	GetLeaf(Tree tree, int i) Gets the ith leaf.
static Tree	GetNumberedCopy(Tree tree) Gets a copy of a tree, with labels replaced by numbers
static List	GetPOSList(Tree tree) Gets a list of the POS of all leaves in a tree
static XRule	GetRule(Tree tree) Given a tree with only two nodes (parent and child), returns an XRule that describes the generation "parent -> child".
static List	GetRules(List trees) Gets a list of all the rules (XRules) needed to generate a list of trees.
static List	GetRules(List trees, boolean isLex) Gets a list of all the rules (XRules) needed to generate a list of trees.
static List	GetRules(Tree tree) Gets a list of all the rules (XRules) needed to generate a given tree.
static List	GetRules(Tree tree, boolean isLex) Gets a list of all the rules (XRules) needed to generate a given tree.
static ArrayList	GetSentence(Tree tree) Gets the sentence represented by a tree (as a list of XLabels).
static String	GetSentenceAsString(Tree tree) Gets the sentence represented by a tree (as a string).
static String	GetSentenceAsString(Tree tree, boolean includeHead, boolean includeTags) Gets the sentence represented by a tree (as a string).
static XTagSet	GetTagSet(Tree tree) Returns a set of all the tags in the tree.
static void	main(String[] args)
static void	Number(Tree tree) Replaces tree node labels with numbers.
static boolean	ParentOfLeaf(Tree tree) Returns true if the tree has only one child (a leaf), false otherwise.
static void	PerkUp(Tree tree, int i, String label) "Perculates" tag info from leaves up through the root
static void	PrintTreeSentences(List trees) prints a list of trees as sentences see GetSentenceAsString
static Tree	ReadTree(String fn) reads a single tree from a file
static List	ReadTrees(String fn) reads a list of trees from a file
static void	SetLabels(Tree tree) Converts tree labels from strings to XLabel.toString().
static void	SetLeaves(Tree tree) Copies tag information from ParentOfLeaves to leaves.
static void	WriteTree(Tree t, String fn) writes a single tree to a file
static void	WriteTrees(List trees, String fn) writes a list of trees to a file

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

startSymbol

public static final String startSymbol

this symbol marks the top of a tree.

See Also:

Constant Field Values

Constructor Detail

TreeUtil

public TreeUtil()

Method Detail

WriteTree

public static void WriteTree(Tree t,
                             String fn)
                      throws IOException

writes a single tree to a file

IOException

ReadTree

public static Tree ReadTree(String fn)
                     throws IOException

reads a single tree from a file

IOException

WriteTrees

public static void WriteTrees(List trees,
                              String fn)
                       throws IOException

writes a list of trees to a file

IOException

ReadTrees

public static List ReadTrees(String fn)
                      throws IOException

reads a list of trees from a file

IOException

PrintTreeSentences

public static void PrintTreeSentences(List trees)

prints a list of trees as sentences see GetSentenceAsString

CopyTags

public static void CopyTags(Tree fromTree,
                            Tree toTree)

copy label tags from fromTree to toTree.

See Also:

XLabel

GetTagSet

public static XTagSet GetTagSet(Tree tree)

Returns a set of all the tags in the tree. The union of each leaf's tags

See Also:

XLabel

GetSentence

public static ArrayList GetSentence(Tree tree)

Gets the sentence represented by a tree (as a list of XLabels).

See Also:

XLabel

GetSentenceAsString

public static String GetSentenceAsString(Tree tree,
                                         boolean includeHead,
                                         boolean includeTags)

Gets the sentence represented by a tree (as a string). Converts each XLabel leaf into a string using parameters includeHead, includeTags

See Also:

XLabel

GetSentenceAsString

public static String GetSentenceAsString(Tree tree)

Gets the sentence represented by a tree (as a string). Includes all head and tag information from leaf XLabels

See Also:

XLabel

GetLeaf

public static Tree GetLeaf(Tree tree,
                           int i)

Gets the ith leaf.

GetPOSList

public static List GetPOSList(Tree tree)

Gets a list of the POS of all leaves in a tree

CleanLabels

public static void CleanLabels(Tree tree)

Strips tag information from all labels in a tree Use Clean(Tree tree, boolean includeTags, boolean includeHead) instead!

SetLabels

public static void SetLabels(Tree tree)

Converts tree labels from strings to XLabel.toString(). Depending on the current XLabel implementation, this may or may not insert brackets after each label

See Also:

XLabel

PerkUp

public static void PerkUp(Tree tree,
                          int i,
                          String label)

"Perculates" tag info from leaves up through the root

See Also:

XLabel

AddTop

public static Tree AddTop(Tree tree)

Adds a new node (with label == startSymbol) to the root of the tree. see startSymbol

See Also:

XLabel

ParentOfLeaf

public static boolean ParentOfLeaf(Tree tree)

Returns true if the tree has only one child (a leaf), false otherwise.

CleanTop

public static void CleanTop(Tree tree)

Removes tag information from the top node in a tree.

See Also:

XLabel

CleanLeaves

public static void CleanLeaves(Tree tree)

Removes tag information from all the nodes in a tree

SetLeaves

public static void SetLeaves(Tree tree)

Copies tag information from ParentOfLeaves to leaves.

See Also:

XLabel

Number

public static void Number(Tree tree)

Replaces tree node labels with numbers. Assigns a unique number to each node depth-first.

GetNumberedCopy

public static Tree GetNumberedCopy(Tree tree)

Gets a copy of a tree, with labels replaced by numbers

See Also:

Number, XLabel

GetRule

public static XRule GetRule(Tree tree)

Given a tree with only two nodes (parent and child), returns an XRule that describes the generation "parent -> child". This XRule has a default probability of 1.

See Also:

XRule

GetRules

public static List GetRules(Tree tree,
                            boolean isLex)

Gets a list of all the rules (XRules) needed to generate a given tree. Each rule has a probability of 1.

Parameters:

isLex - if true, returns only those rules used to generate the bottom layer of the tree (ParentOfChild -> Child). if false returns all rules used to generate tree except those in the bottom layer

See Also:

XRule

GetRules

public static List GetRules(Tree tree)

Gets a list of all the rules (XRules) needed to generate a given tree.

GetRules

public static List GetRules(List trees,
                            boolean isLex)

Gets a list of all the rules (XRules) needed to generate a list of trees.

Parameters:

isLex - if true, returns only those rules used to generate the bottom layer of the tree (ParentOfChild -> Child). if false returns all rules used to generate tree except those in the bottom layer

See Also:

XRule

GetRules

public static List GetRules(List trees)

Gets a list of all the rules (XRules) needed to generate a list of trees.

See Also:

XRule

GetCopy

public static Tree GetCopy(Tree tree)

Makes a deep copy. Creates new Labels as LabeledScoredTreeLeaf or LabeledScoredTreeNode

DoSlyTricks

public static void DoSlyTricks(Tree tree)

GetHeadedCopy

public static Tree GetHeadedCopy(Tree tree)

Gets a copy of tree, including some lexical head information. Currently returns head information for VPs but no other nodes.

Clean

public static void Clean(Tree tree,
                         boolean includeTags,
                         boolean includeHead)

Removes tag and head information from all labels in a tree.

Parameters:

includeTags - true if you don't want to remove tag information

includeHead - true if you don't want to remove head information

main

public static void main(String[] args)
                 throws Exception

Exception