从解析树中获取某些节点 [英] Get certain nodes out of a Parse Tree

问题描述

我正在研究一个涉及通过Hobbs算法进行回指解析的项目。我使用斯坦福解析器解析了我的文本，现在我想操作节点以实现我的算法。

I am working on a project involving anaphora resolution via Hobbs algorithm. I have parsed my text using the Stanford parser, and now I would like to manipulate the nodes in order to implement my algorithm.

此刻，我不明白如何：

• 根据POS标签访问节点（例如，我需要以代词开头 - 我如何获得所有代词？）。

• Access a node based on its POS tag (e.g. I need to start with a pronoun - how do I get all pronouns?).

使用访客。我有点像Java的菜鸟，但是在C ++中我需要实现一个Visitor functor然后处理它的钩子。我找不到Stanford Parser的Tree结构。那是jgrapht吗？如果是的话，你可以在代码片段中提供一些指示吗？

Use visitors. I'm a bit of a noob of Java, but in C++ I needed to implement a Visitor functor and then work on its hooks. I could not find much for the Stanford Parser's Tree structure though. Is that jgrapht? If it is, could you provide me with some pointers at code snippets?

推荐答案

@ dhg的答案很好，但是这里有两个其他选项可能也有用了解：

@dhg's answer works fine, but here are two other options that it might also be useful to know about:

• 树类实现 Iterable 。您可以在预订遍历中迭代遍历树的所有节点，或者严格地说，按每个节点为首的子树：

• The Tree class implements Iterable. You can iterate through all the nodes of a Tree, or, strictly, the subtrees headed by each node, in a pre-order traversal, with:

for (Tree subtree : t) { 
    if (subtree.label().value().equals("PRP")) {
        pronouns.add(subtree);
    }
}

您还可以获得满足的节点一些（可能非常复杂的模式）使用 tregex ，它的行为类似于 java.util.regex ，允许模式匹配在树上。你会有类似的东西：

You can also get just nodes that satisfy some (potentially quite complex pattern) by using tregex, which behaves rather like java.util.regex by allowing pattern matches over trees. You would have something like:

TregexPattern tgrepPattern = TregexPattern.compile("PRP");
TregexMatcher m = tgrepPattern.matcher(t);
while (m.find()) {
    Tree subtree = m.getMatch();
    pronouns.add(subtree);
}

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