nltk.parse.chart.EdgeI

class documentation

class EdgeI(object): (source)

Known subclasses: nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

View In Hierarchy

A hypothesis about the structure of part of a sentence. Each edge records the fact that a structure is (partially) consistent with the sentence. An edge contains:

A span, indicating what part of the sentence is consistent with the hypothesized structure.
A left-hand side, specifying what kind of structure is hypothesized.
A right-hand side, specifying the contents of the hypothesized structure.
A dot position, indicating how much of the hypothesized structure is consistent with the sentence.

Every edge is either complete or incomplete:

An edge is complete if its structure is fully consistent with the sentence.
An edge is incomplete if its structure is partially consistent with the sentence. For every incomplete edge, the span specifies a possible prefix for the edge's structure.

There are two kinds of edge:

A TreeEdge records which trees have been found to be (partially) consistent with the text.
A LeafEdge records the tokens occurring in the text.

The EdgeI interface provides a common interface to both types of edge, allowing chart parsers to treat them in a uniform manner.

Method	`__eq__`	Undocumented
Method	`__hash__`	Undocumented
Method	`__init__`	Undocumented
Method	`__lt__`	Undocumented
Method	`__ne__`	Undocumented
Method	`dot`	Return this edge's dot position, which indicates how much of the hypothesized structure is consistent with the sentence. In particular, `self.rhs[:dot]` is consistent with `tokens[self.start():self.end()]`...
Method	`end`	Return the end index of this edge's span.
Method	`is_complete`	Return True if this edge's structure is fully consistent with the text.
Method	`is_incomplete`	Return True if this edge's structure is partially consistent with the text.
Method	`length`	Return the length of this edge's span.
Method	`lhs`	Return this edge's left-hand side, which specifies what kind of structure is hypothesized by this edge.
Method	`nextsym`	Return the element of this edge's right-hand side that immediately follows its dot.
Method	`rhs`	Return this edge's right-hand side, which specifies the content of the structure hypothesized by this edge.
Method	`span`	Return a tuple `(s, e)`, where `tokens[s:e]` is the portion of the sentence that is consistent with this edge's structure.
Method	`start`	Return the start index of this edge's span.
Instance Variable	`_hash`	Undocumented

def __eq__(self, other): (source) ¶

Undocumented

def __hash__(self): (source) ¶

Undocumented

def __init__(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Undocumented

def __lt__(self, other): (source) ¶

Undocumented

def __ne__(self, other): (source) ¶

Undocumented

def dot(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return this edge's dot position, which indicates how much of the hypothesized structure is consistent with the sentence. In particular, self.rhs[:dot] is consistent with tokens[self.start():self.end()].

Returns
int	Undocumented

def end(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return the end index of this edge's span.

Returns
int	Undocumented

def is_complete(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return True if this edge's structure is fully consistent with the text.

Returns
bool	Undocumented

def is_incomplete(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return True if this edge's structure is partially consistent with the text.

Returns
bool	Undocumented

def length(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return the length of this edge's span.

Returns
int	Undocumented

def lhs(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return this edge's left-hand side, which specifies what kind of structure is hypothesized by this edge.

See Also
`TreeEdge` and `LeafEdge` for a description of the left-hand side values for each edge type.

def nextsym(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return the element of this edge's right-hand side that immediately follows its dot.

Returns
Nonterminal or terminal or None	Undocumented

def rhs(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return this edge's right-hand side, which specifies the content of the structure hypothesized by this edge.

See Also
`TreeEdge` and `LeafEdge` for a description of the right-hand side values for each edge type.

def span(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return a tuple (s, e), where tokens[s:e] is the portion of the sentence that is consistent with this edge's structure.

Returns
tuple(int, int)	Undocumented

def start(self): (source) ¶

overridden in nltk.ccg.chart.CCGEdge, nltk.ccg.chart.CCGLeafEdge, nltk.parse.chart.LeafEdge, nltk.parse.chart.TreeEdge

Return the start index of this edge's span.

Returns
int	Undocumented

_hash = (source) ¶

Undocumented