Named Entity Recognition is the most important, or I would say, the starting step in Information Retrieval. Information Retrieval is the technique to extract important and useful information from unstructured raw text documents. Named Entity Recognition NER works by locating and identifying the named entities present in unstructured text into the standard categories such as person names, locations, organizations, time expressions, quantities, monetary values, percentage, codes etc. Spacy comes with an extremely fast statistical entity recognition system that assigns labels to contiguous spans of tokens.
Spacy Installation and Basic Operations | NLP Text Processing Library | Part 1
Spacy provides an option to add arbitrary classes to entity recognition systems and update the model to even include the new examples apart from already defined entities within the model.
Spacy has the ‘ner’ pipeline component that identifies token spans fitting a predetermined set of named entities. These are available as the ‘ents’ property of a Doc object.
Perform standard imports import spacy nlp = spacy.load('en_core_web_sm') Write a function to display basic entity info: def show_ents(doc): if doc.ents: for ent in doc.ents: print(ent.text+' - ' +str(ent.start_char) +' - '+ str(ent.end_char) +' - '+ent.label_+ ' - '+str(spacy.explain(ent.label_))) else: print('No named entities found.') doc1 = nlp("Apple is looking at buying U.K. startup for $1 billion") show_ents(doc1)
Accessing Entity Annotations The standard way to access entity annotations is the doc.ents property, which produces a sequence of Span objects. The entity type is accessible either as a hash value using ent.label or as a string using ent.label_.
The Span object acts as a sequence of tokens, so you can iterate over the entity or index into it. You can also get the text form of the whole entity, as though it were a single token.
You can also access token entity annotations using the token.ent_iob and token.ent_type attributes. token.ent_iob indicates whether an entity starts continues or ends on the tag. If no entity type is set on a token, it will return an empty string.