qparser module

Parser classes

class whoosh.qparser.QueryParser(default_field, schema=None, conjunction=<class 'whoosh.query.And'>, termclass=<class 'whoosh.query.Term'>)

The default parser for Whoosh, implementing a powerful fielded query language similar to Lucene’s.

Parameters:

• default_field – Use this as the field for any terms without an explicit field. For example, if the query string is “hello f1:there” and the default field is “f2”, the parsed query will be as if the user had entered “f2:hello f1:there”. This argument is required.
• conjuction – Use this query.Query class to join together clauses where the user has not explictly specified a join. For example, if this is query.And, the query string “a b c” will be parsed as “a AND b AND c”. If this is query.Or, the string will be parsed as “a OR b OR c”.
• termclass – Use this query.Query class for bare terms. For example, query.Term or query.Variations.
• schema – An optional fields.Schema object. If this argument is present, the appropriate field will be used to tokenize terms/phrases before they are turned into query objects.

parse(input, normalize=True)

Parses the input string and returns a Query object/tree.

This method may return None if the input string does not result in any valid queries. It may also raise a variety of exceptions if the input string is malformed.

Parameters:

• input – the unicode string to parse.
• normalize – whether to call normalize() on the query object/tree before returning it. This should be left on unless you’re trying to debug the parser output.

Return type:

whoosh.query.Query

class whoosh.qparser.MultifieldParser(fieldnames, schema=None, conjunction=<class 'whoosh.query.And'>, termclass=<class 'whoosh.query.Term'>)

A subclass of QueryParser. Instead of assigning unfielded clauses to a default field, this class transforms them into an OR clause that searches a list of fields. For example, if the list of multi-fields is “f1”, “f2” and the query string is “hello there”, the class will parse “(f1:hello OR f2:hello) (f1:there OR f2:there)”. This is very useful when you have two textual fields (e.g. “title” and “content”) you want to search by default.

class whoosh.qparser.SimpleParser(fieldname, schema=None, termclass=<class 'whoosh.query.Term'>, phraseclass=<class 'whoosh.query.Phrase'>, minmatch=0, minpercent=0.75, phrasefields=None)

class whoosh.qparser.SimpleNgramParser(fieldname, minchars, maxchars, discardspaces=False, analyzerclass=<function NgramAnalyzer at 0x1928668>)

A simple parser that only allows searching a single Ngram field. Breaks the input text into grams. It can either discard grams containing spaces, or compose them as optional clauses to the query.

Parameters:

• fieldname – The field to search.
• minchars – The minimum gram size the text was indexed with.
• maxchars – The maximum gram size the text was indexed with.
• discardspaces – If False, grams containing spaces are made into optional clauses of the query. If True, grams containing spaces are ignored.
• analyzerclass – An analyzer class. The default is the standard NgramAnalyzer. The parser will instantiate this analyzer with the gram size set to the maximum usable size based on the input string.