nltk.grammar.ProbabilisticProduction

class documentation

class ProbabilisticProduction(Production, ImmutableProbabilisticMixIn): (source)

Constructor: ProbabilisticProduction(lhs, rhs, **prob)

A probabilistic context free grammar production. A PCFG ProbabilisticProduction is essentially just a Production that has an associated probability, which represents how likely it is that this production will be used. In particular, the probability of a ProbabilisticProduction records the likelihood that its right-hand side is the correct instantiation for any given occurrence of its left-hand side.

See Also
`Production`

Method	`__eq__`	Return True if this `Production` is equal to `other`.
Method	`__hash__`	Return a hash value for the `Production`.
Method	`__init__`	Construct a new `ProbabilisticProduction`.
Method	`__ne__`	Undocumented
Method	`__str__`	Return a verbose string representation of the `Production`.

Inherited from Production:

Method	`__len__`	Return the length of the right-hand side.
Method	`__lt__`	Undocumented
Method	`__repr__`	Return a concise string representation of the `Production`.
Method	`is_lexical`	Return True if the right-hand contain at least one terminal token.
Method	`is_nonlexical`	Return True if the right-hand side only contains `Nonterminals`
Method	`lhs`	Return the left-hand side of this `Production`.
Method	`rhs`	Return the right-hand side of this `Production`.
Instance Variable	`_lhs`	The left-hand side of the production.
Instance Variable	`_rhs`	The right-hand side of the production.

Inherited from ImmutableProbabilisticMixIn (via Production):

Method	`set_logprob`	Set the log probability associated with this object to `logprob`. I.e., set the probability associated with this object to `2**(logprob)`.
Method	`set_prob`	Set the probability associated with this object to `prob`.

Inherited from ProbabilisticMixIn (via Production, ImmutableProbabilisticMixIn):

Method	`logprob`	Return `log(p)`, where `p` is the probability associated with this object.
Method	`prob`	Return the probability associated with this object.
Instance Variable	`__logprob`	Undocumented
Instance Variable	`__prob`	Undocumented

def __eq__(self, other): (source) ¶

overrides nltk.grammar.Production.__eq__

Return True if this Production is equal to other.

Returns
bool	Undocumented

def __hash__(self): (source) ¶

overrides nltk.grammar.Production.__hash__

Return a hash value for the Production.

Returns
int	Undocumented

def __init__(self, lhs, rhs, **prob): (source) ¶

overrides nltk.grammar.Production.__init__

Construct a new ProbabilisticProduction.

Parameters
lhs:Nonterminal	The left-hand side of the new `ProbabilisticProduction`.
rhs:sequence(Nonterminal and terminal)	The right-hand side of the new `ProbabilisticProduction`.
**prob	Probability parameters of the new `ProbabilisticProduction`.

def __ne__(self, other): (source) ¶

overrides nltk.grammar.Production.__ne__

Undocumented

def __str__(self): (source) ¶

overrides nltk.grammar.Production.__str__

Return a verbose string representation of the Production.

Returns
str	Undocumented