LazyEvalDict#

class LazyEvalDict(eval_function, *args, **kwargs)#

Bases: dict

A dictionary that evaluates values lazily upon access.

This class extends the standard Python dictionary to support lazy evaluation of its values. A user-defined function is applied to the value associated with a key the first time that key is accessed. Subsequent accesses return the already-evaluated value without invoking the evaluation function again. This approach is beneficial in scenarios where the value computation is expensive, and the result is needed only on demand.

Attributes:: _eval_function: Callable function used to lazily evaluate values. _evaluated_keys: Set of keys whose values have already been evaluated.

__init__(eval_function, *args, **kwargs)#

Initializes an instance of a class that performs actions based on a provided evaluation function. Ensures the evaluation function is callable and prepares an internal state to track evaluated keys.

Parameters#

eval_functionCallable: A callable used to perform evaluations. Must be passed and checked for its callable nature.
*args: Positional arguments passed to the base class initializer.
**kwargs: Keyword arguments passed to the base class initializer.

Raises#

TypeError: If eval_function is not callable.

Methods

`__init__`(eval_function, args, *kwargs)	Initializes an instance of a class that performs actions based on a provided evaluation function.
`clear`()
`copy`()
`fromkeys`(iterable[, value])	Create a new dictionary with keys from iterable and values set to value.
`get`(key[, default])	Return the value for key if key is in the dictionary, else default.
`items`()	Return all key-value pairs, forcing evaluation of any unevaluated entries.
`keys`()
`pop`(k[,d])	If the key is not found, return the default if given; otherwise, raise a KeyError.
`popitem`()	Remove and return a (key, value) pair as a 2-tuple.
`setdefault`(key[, default])	Insert key with a value of default if key is not in the dictionary.
`update`([E, ]**F)	If E is present and has a .keys() method, then does: for k in E.keys(): D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]
`values`()	Return all values, forcing evaluation of any unevaluated entries.

clear() → None. Remove all items from D.#

copy() → a shallow copy of D#

classmethod fromkeys(iterable, value=None, /)#: Create a new dictionary with keys from iterable and values set to value.

get(key, default=None, /)#: Return the value for key if key is in the dictionary, else default.

items()#: Return all key-value pairs, forcing evaluation of any unevaluated entries.

keys() → a set-like object providing a view on D's keys#

pop(k[, d]) → v, remove specified key and return the corresponding value.#: If the key is not found, return the default if given; otherwise, raise a KeyError.

popitem()#

Remove and return a (key, value) pair as a 2-tuple.

Pairs are returned in LIFO (last-in, first-out) order. Raises KeyError if the dict is empty.

setdefault(key, default=None, /)#

Insert key with a value of default if key is not in the dictionary.

Return the value for key if key is in the dictionary, else default.

update([E, ]**F) → None. Update D from mapping/iterable E and F.#: If E is present and has a .keys() method, then does: for k in E.keys(): D[k] = E[k] If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v In either case, this is followed by: for k in F: D[k] = F[k]

values()#: Return all values, forcing evaluation of any unevaluated entries.