解析和词性标注有什么区别？

Question

I know that POS tagging labels each and every word in a sentence with its appropriate Part Of Speech, But isn't that what a Parser does too? ie, break a sentence into its component parts? I've looked this up on the internet but couldn't find any satisfactory explanation. Please clear my doubt. Thanks in advance

Answer 1

They are two distinct procedures:

• POS Tagging: each token gets assigned a label which reflects its word class.

• Parsing: each sentence gets assigned a structure (often a tree) which reflects how its components are related to each other.

POS Tagging takes a tokenised sequence of words, and returns a list of annotated tokens, where each token has a word class label. This is often disambiguated by looking at the context surrounding the token.

There is also chunking , which groups tokens into related groups (such as noun phrases). Chunks are non-overlapping sequences.

Parsing commonly results in a parse tree for a sentence; often there can be many possible trees in case of ambiguous sentences.

POS tagging is usually a preparatory step in parsing, as a parser typically operates on word classes (though there are some parsing algorithms that work with tokens directly, or a mixture of tags and tokens).