+ h$.^RIHtHt!RR]R7tR#))ABCMetaabstractmethodca]tRt^ toRtRtRtRRltRt] R4t Rt ] RRl4t R t R tR tR tR tRtRtRt]]R44tRtVtR#)Featurea An abstract base class for Features. A Feature is a combination of a specific property-computing method and a list of relative positions to apply that method to. The property-computing method, M{extract_property(tokens, index)}, must be implemented by every subclass. It extracts or computes a specific property for the token at the current index. Typical extract_property() methods return features such as the token text or tag; but more involved methods may consider the entire sequence M{tokens} and for instance compute the length of the sentence the token belongs to. In addition, the subclass may have a PROPERTY_NAME, which is how it will be printed (in Rules and Templates, etc). If not given, defaults to the classname. znltk.tbl.FeatureNc  RVnVf4\\VUu0uFp\V4kK up44VnM-W8d\h\\ W^,44VnVPP;'gVPPVn R#uupi \d!p\ RPY44ThRp?ii;i)a| Construct a Feature which may apply at C{positions}. >>> # For instance, importing some concrete subclasses (Feature is abstract) >>> from nltk.tag.brill import Word, Pos >>> # Feature Word, applying at one of [-2, -1] >>> Word([-2,-1]) Word([-2, -1]) >>> # Positions need not be contiguous >>> Word([-2,-1, 1]) Word([-2, -1, 1]) >>> # Contiguous ranges can alternatively be specified giving the >>> # two endpoints (inclusive) >>> Pos(-3, -1) Pos([-3, -2, -1]) >>> # In two-arg form, start <= end is enforced >>> Pos(2, 1) Traceback (most recent call last): File "", line 1, in File "nltk/tbl/template.py", line 306, in __init__ raise TypeError ValueError: illegal interval specification: (start=2, end=1) :type positions: list of int :param positions: the positions at which this features should apply :raises ValueError: illegal position specifications An alternative calling convention, for contiguous positions only, is Feature(start, end): :type start: int :param start: start of range where this feature should apply :type end: int :param end: end of range (NOTE: inclusive!) where this feature should apply Nz2illegal interval specification: (start={}, end={})) positionstuplesortedint TypeErrorrange ValueErrorformat __class__ PROPERTY_NAME__name__)selfrendies&&& 2/usr/lib/python3/dist-packages/nltk/tbl/feature.py__init__Feature.__init__#sP ;"69*E9a3q69*E#FGDN ?#O!&uYa'@!A"^^99TTT^^=T=T+F   HOO!  sB' ,B,, C7CCcVP#N)rrs&rencode_json_objFeature.encode_json_obj^s ~~cTpV!V4#r)clsobjrs&& rdecode_json_objFeature.decode_json_objas 9~rcbVPP R\VP4: R2#)())rrlistrrs&r__repr__Feature.__repr__fs*..))*!D,@+C1EErc a\;QJdRV4F 'dK RM RM !RV44'g\RV 24hV3RlV4pVUu.uFqS'd ^V9dKV!V4NK up#uupi)a Return a list of features, one for each start point in starts and for each window length in winlen. If excludezero is True, no Features containing 0 in its positions will be generated (many tbl trainers have a special representation for the target feature at [0]) For instance, importing a concrete subclass (Feature is abstract) >>> from nltk.tag.brill import Word First argument gives the possible start positions, second the possible window lengths >>> Word.expand([-3,-2,-1], [1]) [Word([-3]), Word([-2]), Word([-1])] >>> Word.expand([-2,-1], [1]) [Word([-2]), Word([-1])] >>> Word.expand([-3,-2,-1], [1,2]) [Word([-3]), Word([-2]), Word([-1]), Word([-3, -2]), Word([-2, -1])] >>> Word.expand([-2,-1], [1]) [Word([-2]), Word([-1])] A third optional argument excludes all Features whose positions contain zero >>> Word.expand([-2,-1,0], [1,2], excludezero=False) [Word([-2]), Word([-1]), Word([0]), Word([-2, -1]), Word([-1, 0])] >>> Word.expand([-2,-1,0], [1,2], excludezero=True) [Word([-2]), Word([-1]), Word([-2, -1])] All window lengths must be positive >>> Word.expand([-2,-1], [0]) Traceback (most recent call last): File "", line 1, in File "nltk/tag/tbl/template.py", line 371, in expand :param starts: where to start looking for Feature ValueError: non-positive window length in [0] :param starts: where to start looking for Feature :type starts: list of ints :param winlens: window lengths where to look for Feature :type starts: list of ints :param excludezero: do not output any Feature with 0 in any of its positions. :type excludezero: bool :returns: list of Features :raises ValueError: for non-positive window lengths c3*"TF q^8xK R#5i)rNr!).0xs& r !Feature.expand..s*'Qq5'sFTznon-positive window length in c3<"TF9p\\S4V, ^,4FpSW"V,xK K; R#5i)N)r len)r.wrstartss& rr0r1s7 UA%F aRS@S:TQfQQ:TsAA)allr)r"r6winlens excludezeroxsr/s&f&& rexpandFeature.expandisjls*'*sss*'***=gYGH H U U "C1;16ACCCs A>/ A>c VPVPJ;'d,\VP4\VP48#)a Return True if this Feature always returns True when other does More precisely, return True if this feature refers to the same property as other; and this Feature looks at all positions that other does (and possibly other positions in addition). #For instance, importing a concrete subclass (Feature is abstract) >>> from nltk.tag.brill import Word, Pos >>> Word([-3,-2,-1]).issuperset(Word([-3,-2])) True >>> Word([-3,-2,-1]).issuperset(Word([-3,-2, 0])) False #Feature subclasses must agree >>> Word([-3,-2,-1]).issuperset(Pos([-3,-2])) False :param other: feature with which to compare :type other: (subclass of) Feature :return: True if this feature is superset, otherwise False :rtype: bool )rsetrrothers&&r issupersetFeature.issupersetsB8~~0  S5HC OOM 6  rc \VPVPJ;'d0\VP4\VP4,4#)a Return True if the positions of this Feature intersects with those of other More precisely, return True if this feature refers to the same property as other; and there is some overlap in the positions they look at. #For instance, importing a concrete subclass (Feature is abstract) >>> from nltk.tag.brill import Word, Pos >>> Word([-3,-2,-1]).intersects(Word([-3,-2])) True >>> Word([-3,-2,-1]).intersects(Word([-3,-2, 0])) True >>> Word([-3,-2,-1]).intersects(Word([0])) False #Feature subclasses must agree >>> Word([-3,-2,-1]).intersects(Pos([-3,-2])) False :param other: feature with which to compare :type other: (subclass of) Feature :return: True if feature classes agree and there is some overlap in the positions they look at :rtype: bool )boolrr>rr?s&&r intersectsFeature.intersectssE: NNeoo - ; ;DNN#c%//&::  rctVPVPJ;'dVPVP8H#r)rrr?s&&r__eq__Feature.__eq__s*~~0VVT^^u5VVrcVPPVPP8;'gVPVP8#r)rrrr?s&&r__lt__Feature.__lt__s? NN # #eoo&>&> > - - NNU__ ,  rc W8X*#rr!r?s&&r__ne__Feature.__ne__s ""rc W8#rr!r?s&&r__gt__Feature.__gt__s |rc W8*#rr!r?s&&r__ge__Feature.__ge__s rc"W8;'gW8H#rr!r?s&&r__le__Feature.__le__s|,,t},rc R#)a Any subclass of Feature must define static method extract_property(tokens, index) :param tokens: the sequence of tokens :type tokens: list of tokens :param index: the current index :type index: int :return: feature value :rtype: any (but usually scalar) Nr!)tokensindexs&&rextract_propertyFeature.extract_propertysr)rrr)F)r __module__ __qualname____firstlineno____doc__json_tagrrr classmethodr$r*r;rArErHrKrNrQrTrW staticmethodrr\__static_attributes____classdictcell__) __classdict__s@rrr s$"HM9UvF8D8Dt @  HW # -    rr) metaclassN)abcrrrr!rrrjs(~ ~ r