Knowledge Graphs in Memory#

KGX makes use of an in-memory labelled property graph for representing a Knowledge Graph.

To support a wide variety of graph libraries, KGX has a Graph API which abstracts over the underlying graph store.

Should you want to add support for a new graph store,

create a new class that extends kgx.graph.base_graph.BaseGraph.
modify the graph_store variable in kgx/config.yml.

kgx.graph.base_graph.BaseGraph#

BaseGraph is the base Graph API that can be used to abstract over any graph, as long as the graph is capable of successfully representing a property graph.

class kgx.graph.base_graph.BaseGraph[source]#

Bases: object

BaseGraph that is a wrapper and provides methods to interact with a graph store.

All implementations should extend this BaseGraph class and implement all the defined methods.

add_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None, **kwargs: Any) → Any[source]#

Add an edge to the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
kwargs (Any) – Any additional edge properties

Return type:

Any

add_edge_attribute(subject_node: str, object_node: str, edge_key: Optional[str], attr_key: str, attr_value: Any) → Any[source]#

Add an attribute to a given edge.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
attr_key (str) – The attribute key
attr_value (Any) – The attribute value

Return type:

Any

add_node(node: str, **kwargs: Any) → Any[source]#

Add a node to the graph.

Parameters:

node (str) – Node identifier
**kwargs (Any) – Any additional node properties

add_node_attribute(node: str, key: str, value: Any) → Any[source]#

Add an attribute to a given node.

Parameters:

node (str) – The node identifier
key (str) – The key for an attribute
value (Any) – The value corresponding to the key

Return type:

Any

clear() → None[source]#: Remove all the nodes and edges in the graph.

degree()[source]#: Get the degree of all the nodes in a graph.

edges(keys: bool = False, data: bool = True) → Dict[source]#

Get all edges in a graph.

Parameters:

keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A dictionary of edges

Return type:

Dict

edges_iter() → Generator[source]#

Get an iterable to traverse through all the edges in a graph.

Returns:: A generator for edges
Return type:: Generator

get_edge(subject_node: str, object_node: str, edge_key: Optional[str]) → Dict[source]#

Get an edge and its properties.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

Returns:

The edge dictionary

Return type:

Dict

static get_edge_attributes(graph: Any, attr_key: str) → Any[source]#

Get all edges that have a value for the given attribute attr_key.

Parameters:

graph (Any) – The graph to modify
attr_key (str) – The attribute key

Return type:

Any

get_node(node: str) → Dict[source]#

Get a node and its properties.

Parameters:: node (str) – The node identifier
Returns:: The node dictionary
Return type:: Dict

static get_node_attributes(graph: Any, attr_key: str) → Any[source]#

Get all nodes that have a value for the given attribute attr_key.

Parameters:

graph (Any) – The graph to modify
attr_key (str) – The attribute key

Return type:

Any

has_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None) → bool[source]#

Check whether a given edge exists in the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

Returns:

Whether or not the given edge exists

Return type:

bool

has_node(node: str) → bool[source]#

Check whether a given node exists in the graph.

Parameters:: node (str) – The node identifier
Returns:: Whether or not the given node exists
Return type:: bool

in_edges(node: str, keys: bool = False, data: bool = False) → List[source]#

Get all incoming edges for a given node.

Parameters:

node (str) – The node identifier
keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A list of edges

Return type:

List

nodes(data: bool = True) → Dict[source]#

Get all nodes in a graph.

Parameters:: data (bool) – Whether or not to fetch node properties
Returns:: A dictionary of nodes
Return type:: Dict

nodes_iter() → Generator[source]#

Get an iterable to traverse through all the nodes in a graph.

Returns:: A generator for nodes
Return type:: Generator

number_of_edges() → int[source]#

Returns the number of edges in a graph.

Return type:: int

number_of_nodes() → int[source]#

Returns the number of nodes in a graph.

Return type:: int

out_edges(node: str, keys: bool = False, data: bool = False) → List[source]#

Get all outgoing edges for a given node.

Parameters:

node (str) – The node identifier
keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A list of edges

Return type:

List

static relabel_nodes(graph: Any, mapping: Dict) → Any[source]#

Relabel identifiers for a series of nodes based on mappings.

Parameters:

graph (Any) – The graph to modify
mapping (Dict[str, str]) – A dictionary of mapping where the key is the old identifier and the value is the new identifier.

Return type:

Any

remove_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None) → Any[source]#

Remove a given edge from the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

Return type:

Any

remove_node(node: str) → Any[source]#

Remove a given node from the graph.

Parameters:: node (str) – The node identifier
Return type:: Any

static set_edge_attributes(graph: Any, attributes: Dict) → Any[source]#

Set nodes attributes from a dictionary of key-values.

Parameters:

graph (Any) – The graph to modify
attributes (Dict) – A dictionary of node identifier to key-value pairs

Return type:

Any

static set_node_attributes(graph: Any, attributes: Dict) → Any[source]#

Set nodes attributes from a dictionary of key-values.

Parameters:

graph (Any) – The graph to modify
attributes (Dict) – A dictionary of node identifier to key-value pairs

Return type:

Any

update_edge_attribute(subject_node: str, object_node: str, edge_key: Optional[str], attr_key: str, attr_value: Any) → Dict[source]#

Update an attribute of a given edge.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
attr_key (str) – The attribute key
attr_value (Any) – The attribute value

Returns:

A dictionary corresponding to the updated edge properties

Return type:

Dict

update_node_attribute(node, key: str, value: Any) → Dict[source]#

Update an attribute of a given node.

Parameters:

node (str) – The node identifier
key (str) – The key for an attribute
value (Any) – The value corresponding to the key

Returns:

A dictionary corresponding to the updated node properties

Return type:

Dict

kgx.graph.nx_graph.NxGraph#

NxGraph is basically an abstraction on top of networkx.MultiDiGraph.

The NxGraph subclasses kgx.graph.base_graph.BaseGraph and implements all the methods defined in BaseGraph.

class kgx.graph.nx_graph.NxGraph[source]#

Bases: BaseGraph

NxGraph is a wrapper that provides methods to interact with a networkx.MultiDiGraph.

NxGraph extends kgx.graph.base_graph.BaseGraph and implements all the methods from BaseGraph.

add_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None, **kwargs: Any) → None[source]#

Add an edge to the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
kwargs (Any) – Any additional edge properties

add_edge_attribute(subject_node: str, object_node: str, edge_key: Optional[str], attr_key: str, attr_value: Any) → None[source]#

Add an attribute to a given edge.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
attr_key (str) – The attribute key
attr_value (Any) – The attribute value

add_node(node: str, **kwargs: Any) → None[source]#

Add a node to the graph.

Parameters:

node (str) – Node identifier
**kwargs (Any) – Any additional node properties

add_node_attribute(node: str, attr_key: str, attr_value: Any) → None[source]#

Add an attribute to a given node.

Parameters:

node (str) – The node identifier
attr_key (str) – The key for an attribute
attr_value (Any) – The value corresponding to the key

clear() → None[source]#: Remove all the nodes and edges in the graph.

degree()[source]#: Get the degree of all the nodes in a graph.

edges(keys: bool = False, data: bool = True) → Dict[source]#

Get all edges in a graph.

Parameters:

keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A dictionary of edges

Return type:

Dict

edges_iter() → Generator[source]#

Get an iterable to traverse through all the edges in a graph.

Returns:: A generator for edges where each element is a 4-tuple that contains (subject, object, edge_key, edge_data)
Return type:: Generator

get_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None) → Dict[source]#

Get an edge and its properties.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

Returns:

The edge dictionary

Return type:

Dict

static get_edge_attributes(graph: BaseGraph, attr_key: str) → Dict[source]#

Get all edges that have a value for the given attribute attr_key.

Parameters:

graph (kgx.graph.base_graph.BaseGraph) – The graph to modify
attr_key (str) – The attribute key

Returns:

A dictionary where edges are the keys and the values are the attribute values for attr_key

Return type:

Dict

get_node(node: str) → Dict[source]#

Get a node and its properties.

Parameters:: node (str) – The node identifier
Returns:: The node dictionary
Return type:: Dict

static get_node_attributes(graph: BaseGraph, attr_key: str) → Dict[source]#

Get all nodes that have a value for the given attribute attr_key.

Parameters:

graph (kgx.graph.base_graph.BaseGraph) – The graph to modify
attr_key (str) – The attribute key

Returns:

A dictionary where nodes are the keys and the values are the attribute values for key

Return type:

Dict

has_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None) → bool[source]#

Check whether a given edge exists in the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

Returns:

Whether or not the given edge exists

Return type:

bool

has_node(node: str) → bool[source]#

Check whether a given node exists in the graph.

Parameters:: node (str) – The node identifier
Returns:: Whether or not the given node exists
Return type:: bool

in_edges(node: str, keys: bool = False, data: bool = False) → List[source]#

Get all incoming edges for a given node.

Parameters:

node (str) – The node identifier
keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A list of edges

Return type:

List

nodes(data: bool = True) → Dict[source]#

Get all nodes in a graph.

Parameters:: data (bool) – Whether or not to fetch node properties
Returns:: A dictionary of nodes
Return type:: Dict

nodes_iter() → Generator[source]#

Get an iterable to traverse through all the nodes in a graph.

Returns:: A generator for nodes where each element is a Tuple that contains (node_id, node_data)
Return type:: Generator

number_of_edges() → int[source]#

Returns the number of edges in a graph.

Return type:: int

number_of_nodes() → int[source]#

Returns the number of nodes in a graph.

Return type:: int

out_edges(node: str, keys: bool = False, data: bool = False) → List[source]#

Get all outgoing edges for a given node.

Parameters:

node (str) – The node identifier
keys (bool) – Whether or not to include edge keys
data (bool) – Whether or not to fetch node properties

Returns:

A list of edges

Return type:

List

static relabel_nodes(graph: BaseGraph, mapping: Dict) → None[source]#

Relabel identifiers for a series of nodes based on mappings.

Parameters:

graph (kgx.graph.base_graph.BaseGraph) – The graph to modify
mapping (Dict) – A dictionary of mapping where the key is the old identifier and the value is the new identifier.

remove_edge(subject_node: str, object_node: str, edge_key: Optional[str] = None) → None[source]#

Remove a given edge from the graph.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key

remove_node(node: str) → None[source]#

Remove a given node from the graph.

Parameters:: node (str) – The node identifier

static set_edge_attributes(graph: BaseGraph, attributes: Dict) → None[source]#

Set nodes attributes from a dictionary of key-values.

Parameters:

graph (kgx.graph.base_graph.BaseGraph) – The graph to modify
attributes (Dict) – A dictionary of node identifier to key-value pairs

Return type:

Any

static set_node_attributes(graph: BaseGraph, attributes: Dict) → None[source]#

Set nodes attributes from a dictionary of key-values.

Parameters:

graph (kgx.graph.base_graph.BaseGraph) – The graph to modify
attributes (Dict) – A dictionary of node identifier to key-value pairs

update_edge_attribute(subject_node: str, object_node: str, edge_key: Optional[str], attr_key: str, attr_value: Any, preserve: bool = False) → Dict[source]#

Update an attribute of a given edge.

Parameters:

subject_node (str) – The subject (source) node
object_node (str) – The object (target) node
edge_key (Optional[str]) – The edge key
attr_key (str) – The attribute key
attr_value (Any) – The attribute value
preserve (bool) – Whether or not to preserve existing values for the given attr_key

Returns:

A dictionary corresponding to the updated edge properties

Return type:

Dict

update_node_attribute(node: str, attr_key: str, attr_value: Any, preserve: bool = False) → Dict[source]#

Update an attribute of a given node.

Parameters:

node (str) – The node identifier
attr_key (str) – The key for an attribute
attr_value (Any) – The value corresponding to the key
preserve (bool) – Whether or not to preserve existing values for the given attr_key

Returns:

A dictionary corresponding to the updated node properties

Return type:

Dict