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Distribution

dstz.core.distribution

Evidence

Bases: dict

A dictionary subclass for storing evidence data.

Evidence enforces type constraints, requiring that all keys be instances of the Item class and all values be floats. This structure is fundamental for representing belief masses in evidence theory.

It behaves like a standard dictionary but adds validation during initialization and item assignment.

Source code in dstz/core/distribution.py 
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class Evidence(dict):
    """A dictionary subclass for storing evidence data.

    `Evidence` enforces type constraints, requiring that all keys be instances
    of the `Item` class and all values be floats. This structure is fundamental
    for representing belief masses in evidence theory.

    It behaves like a standard dictionary but adds validation during
    initialization and item assignment.
    """

    def __init__(self, *args, **kwargs):
        """Initializes the Evidence dictionary.

        This constructor accepts the same arguments as a standard `dict`.
        After initializing, it validates that all keys are instances of `Item`
        and all values are floats.

        Args:
            *args: Variable length argument list, passed to the `dict` constructor.
            **kwargs: Arbitrary keyword arguments, passed to the `dict` constructor.

        Raises:
            TypeError: If any key is not an `Item` instance or any value is not
                a float.
        """
        super(Evidence, self).__init__(*args, **kwargs)
        for key, value in self.items():
            if not isinstance(key, Item):
                raise TypeError('Key must be an instance of Item')
            if not isinstance(value, float):
                raise TypeError('Value must be a float')

    def __setitem__(self, key, value):
        """Sets a key-value pair in the dictionary with type validation.

        Before adding or updating a key-value pair, this method ensures the
        key is an `Item` instance and the value is a float.

        Args:
            key (Item): The key to set, which must be an instance of `Item`.
            value (float): The value to associate with the key.

        Raises:
            TypeError: If the key is not an `Item` instance or the value is
                not a float.
        """
        if not isinstance(key, Item):
            raise TypeError('Key must be an instance of Item')
        if not isinstance(value, float):
            raise TypeError('Value must be a float')
        super(Evidence, self).__setitem__(key, value)

    def __getitem__(self, item):
        """Retrieves an item from the dictionary.

        This method ensures that the key used for retrieval is an instance of
        `Item` before accessing the value.

        Args:
            item (Item): The key whose associated value is to be returned.

        Returns:
            float: The value associated with the given key.

        Raises:
            TypeError: If the key is not an `Item` instance.
        """
        if not isinstance(item, Item):
            raise TypeError('Key must be an instance of Item')
        return super(Evidence, self).__getitem__(item)

__getitem__(item)

Retrieves an item from the dictionary.

This method ensures that the key used for retrieval is an instance of Item before accessing the value.

Parameters:

Name Type Description Default
item Item

The key whose associated value is to be returned.

 required

Returns:

Name Type Description
float

The value associated with the given key.

Raises:

Type Description
TypeError

If the key is not an Item instance.
Source code in dstz/core/distribution.py 
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def __getitem__(self, item):
    """Retrieves an item from the dictionary.

    This method ensures that the key used for retrieval is an instance of
    `Item` before accessing the value.

    Args:
        item (Item): The key whose associated value is to be returned.

    Returns:
        float: The value associated with the given key.

    Raises:
        TypeError: If the key is not an `Item` instance.
    """
    if not isinstance(item, Item):
        raise TypeError('Key must be an instance of Item')
    return super(Evidence, self).__getitem__(item)

__init__(*args, **kwargs)

Initializes the Evidence dictionary.

This constructor accepts the same arguments as a standard dict. After initializing, it validates that all keys are instances of Item and all values are floats.

Parameters:

Name Type Description Default
*args

Variable length argument list, passed to the dict constructor.

 ()
**kwargs

Arbitrary keyword arguments, passed to the dict constructor.

 {}

Raises:

Type Description
TypeError

If any key is not an Item instance or any value is not a float.
Source code in dstz/core/distribution.py 
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def __init__(self, *args, **kwargs):
    """Initializes the Evidence dictionary.

    This constructor accepts the same arguments as a standard `dict`.
    After initializing, it validates that all keys are instances of `Item`
    and all values are floats.

    Args:
        *args: Variable length argument list, passed to the `dict` constructor.
        **kwargs: Arbitrary keyword arguments, passed to the `dict` constructor.

    Raises:
        TypeError: If any key is not an `Item` instance or any value is not
            a float.
    """
    super(Evidence, self).__init__(*args, **kwargs)
    for key, value in self.items():
        if not isinstance(key, Item):
            raise TypeError('Key must be an instance of Item')
        if not isinstance(value, float):
            raise TypeError('Value must be a float')

__setitem__(key, value)

Sets a key-value pair in the dictionary with type validation.

Before adding or updating a key-value pair, this method ensures the key is an Item instance and the value is a float.

Parameters:

Name Type Description Default
key Item

The key to set, which must be an instance of Item.

 required
value float

The value to associate with the key.

 required

Raises:

Type Description
TypeError

If the key is not an Item instance or the value is not a float.
Source code in dstz/core/distribution.py 
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def __setitem__(self, key, value):
    """Sets a key-value pair in the dictionary with type validation.

    Before adding or updating a key-value pair, this method ensures the
    key is an `Item` instance and the value is a float.

    Args:
        key (Item): The key to set, which must be an instance of `Item`.
        value (float): The value to associate with the key.

    Raises:
        TypeError: If the key is not an `Item` instance or the value is
            not a float.
    """
    if not isinstance(key, Item):
        raise TypeError('Key must be an instance of Item')
    if not isinstance(value, float):
        raise TypeError('Value must be a float')
    super(Evidence, self).__setitem__(key, value)