nltk.grammar.Production

class documentation

class Production(object): (source)

Known subclasses: nltk.grammar.DependencyProduction, nltk.grammar.ProbabilisticProduction

Constructor: Production(lhs, rhs)

A grammar production. Each production maps a single symbol on the "left-hand side" to a sequence of symbols on the "right-hand side". (In the case of context-free productions, the left-hand side must be a Nonterminal, and the right-hand side is a sequence of terminals and Nonterminals.) "terminals" can be any immutable hashable object that is not a Nonterminal. Typically, terminals are strings representing words, such as "dog" or "under".

See Also
`CFG`
`DependencyGrammar`
`Nonterminal`

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 `Production`.
Method	`__len__`	Return the length of the right-hand side.
Method	`__lt__`	Undocumented
Method	`__ne__`	Undocumented
Method	`__repr__`	Return a concise string representation of the `Production`.
Method	`__str__`	Return a verbose 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.

def __eq__(self, other): (source) ¶

overridden in nltk.grammar.ProbabilisticProduction

Return True if this Production is equal to other.

Returns
bool	Undocumented

def __hash__(self): (source) ¶

overridden in nltk.grammar.ProbabilisticProduction

Return a hash value for the Production.

Returns
int	Undocumented

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

overridden in nltk.grammar.ProbabilisticProduction

Construct a new Production.

Parameters
lhs:Nonterminal	The left-hand side of the new `Production`.
rhs:sequence(Nonterminal and terminal)	The right-hand side of the new `Production`.

def __len__(self): (source) ¶

Return the length of the right-hand side.

Returns
int	Undocumented

def __lt__(self, other): (source) ¶

Undocumented

def __ne__(self, other): (source) ¶

overridden in nltk.grammar.ProbabilisticProduction

Undocumented

def __repr__(self): (source) ¶

Return a concise string representation of the Production.

Returns
str	Undocumented

def __str__(self): (source) ¶

overridden in nltk.grammar.DependencyProduction, nltk.grammar.ProbabilisticProduction

Return a verbose string representation of the Production.

Returns
str	Undocumented

def is_lexical(self): (source) ¶

Return True if the right-hand contain at least one terminal token.

Returns
bool	Undocumented

def is_nonlexical(self): (source) ¶

Return True if the right-hand side only contains Nonterminals

Returns
bool	Undocumented

def lhs(self): (source) ¶

Return the left-hand side of this Production.

Returns
Nonterminal	Undocumented

def rhs(self): (source) ¶

Return the right-hand side of this Production.

Returns
sequence(Nonterminal and terminal)	Undocumented

_lhs: Nonterminal = (source) ¶

The left-hand side of the production.

_rhs: tuple(Nonterminal, terminal) = (source) ¶

The right-hand side of the production.