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🌼 DAGNode

bigtree.node.dagnode

DAGNode 

DAGNode(name='', parents=None, children=None, **kwargs)

Base DAGNode extends any Python class to a DAG node, for DAG implementation. In DAG implementation, a node can have multiple parents.

Parents and children cannot be reassigned once assigned, as Nodes are allowed to have multiple parents and children. If each node only has one parent, use Node class. DAGNodes can have attributes if they are initialized from DAGNode or dictionary.

DAGNode can be linked to each other with parents and children setter methods, or using bitshift operator with the convention parent_node >> child_node or child_node << parent_node.

Examples:

>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> c.parents = [a, b]
>>> c.children = [d]

>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> a >> c
>>> b >> c
>>> d << c

Directly passing parents argument.

>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c", parents=[a, b])
>>> d = DAGNode("d", parents=[c])

Directly passing children argument.

>>> from bigtree import DAGNode
>>> d = DAGNode("d")
>>> c = DAGNode("c", children=[d])
>>> b = DAGNode("b", children=[c])
>>> a = DAGNode("a", children=[c])

DAGNode Creation

Node can be created by instantiating a DAGNode class or by using a dictionary. If node is created with dictionary, all keys of dictionary will be stored as class attributes.

>>> from bigtree import DAGNode
>>> a = DAGNode.from_dict({"name": "a", "age": 90})

DAGNode Attributes

These are node attributes that have getter and/or setter methods.

Get and set other DAGNode

  1. parents: Get/set parent nodes
  2. children: Get/set child nodes

Get other DAGNode

  1. ancestors: Get ancestors of node excluding self, iterator
  2. descendants: Get descendants of node excluding self, iterator
  3. siblings: Get siblings of self

Get DAGNode configuration

  1. node_name: Get node name, without accessing name directly
  2. is_root: Get indicator if self is root node
  3. is_leaf: Get indicator if self is leaf node

DAGNode Methods

These are methods available to be performed on DAGNode.

Constructor methods

  1. from_dict(): Create DAGNode from dictionary

DAGNode methods

  1. describe(): Get node information sorted by attributes, return list of tuples
  2. get_attr(attr_name: str): Get value of node attribute
  3. set_attrs(attrs: dict): Set node attribute name(s) and value(s)
  4. go_to(node: Self): Get a path from own node to another node from same DAG
  5. copy(): Deep copy self

parent property writable 

parent

Do not allow parent attribute to be accessed

Raises:

Type Description
AttributeError

No such attribute

parents property writable 

parents

Get parent nodes

Returns:

Type Description
Iterable[T]

(Iterable[Self])

children deletable property writable 

children

Get child nodes

Returns:

Type Description
Iterable[T]

(Iterable[Self])

ancestors property 

ancestors

Get iterator to yield all ancestors of self, does not include self

Returns:

Type Description
Iterable[T]

(Iterable[Self])

descendants property 

descendants

Get iterator to yield all descendants of self, does not include self

Returns:

Type Description
Iterable[T]

(Iterable[Self])

siblings property 

siblings

Get siblings of self

Returns:

Type Description
Iterable[T]

(Iterable[Self])

node_name property 

node_name

Get node name

Returns:

Type Description
str

(str)

is_root property 

is_root

Get indicator if self is root node

Returns:

Type Description
bool

(bool)

is_leaf property 

is_leaf

Get indicator if self is leaf node

Returns:

Type Description
bool

(bool)

from_dict classmethod 

from_dict(input_dict)

Construct node from dictionary, all keys of dictionary will be stored as class attributes Input dictionary must have key name if not Node will not have any name

Examples:

>>> from bigtree import DAGNode
>>> a = DAGNode.from_dict({"name": "a", "age": 90})

Parameters:

Name Type Description Default
input_dict Dict[str, Any]

dictionary with node information, key: attribute name, value: attribute value

 required

Returns:

Type Description
DAGNode

(DAGNode)

describe 

describe(exclude_attributes=[], exclude_prefix='')

Get node information sorted by attribute name, returns list of tuples

Parameters:

Name Type Description Default
exclude_attributes List[str]

list of attributes to exclude

 []
exclude_prefix str

prefix of attributes to exclude

 ''

Returns:

Type Description
List[Tuple[str, Any]]

(List[Tuple[str, Any]])

get_attr 

get_attr(attr_name, default_value=None)

Get value of node attribute Returns default value if attribute name does not exist

Parameters:

Name Type Description Default
attr_name str

attribute name

 required
default_value Any

default value if attribute does not exist, defaults to None

 None

Returns:

Type Description
Any

(Any)

set_attrs 

set_attrs(attrs)

Set node attributes

Examples:

>>> from bigtree.node.dagnode import DAGNode
>>> a = DAGNode('a')
>>> a.set_attrs({"age": 90})
>>> a
DAGNode(a, age=90)

Parameters:

Name Type Description Default
attrs Dict[str, Any]

attribute dictionary, key: attribute name, value: attribute value

 required

go_to 

go_to(node)

Get list of possible paths from current node to specified node from same tree

Examples:

>>> from bigtree import DAGNode
>>> a = DAGNode("a")
>>> b = DAGNode("b")
>>> c = DAGNode("c")
>>> d = DAGNode("d")
>>> a >> c
>>> b >> c
>>> c >> d
>>> a >> d
>>> a.go_to(c)
[[DAGNode(a, ), DAGNode(c, )]]
>>> a.go_to(d)
[[DAGNode(a, ), DAGNode(c, ), DAGNode(d, )], [DAGNode(a, ), DAGNode(d, )]]
>>> a.go_to(b)
Traceback (most recent call last):
    ...
bigtree.utils.exceptions.TreeError: It is not possible to go to DAGNode(b, )

Parameters:

Name Type Description Default
node Self

node to travel to from current node, inclusive of start and end node

 required

Returns:

Type Description
List[List[T]]

(List[List[Self]])

copy 

copy()

Deep copy self; clone DAGNode

Examples:

>>> from bigtree.node.dagnode import DAGNode
>>> a = DAGNode('a')
>>> a_copy = a.copy()

Returns:

Type Description
T

(Self)