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EdgesArray API Reference

Type: groggy.EdgesArray


Overview

Array of edge IDs with edge-specific operations.

Primary Use Cases: - Working with collections of edge IDs - Edge set operations - Batch edge queries

Related Objects: - NumArray - EdgesAccessor


Complete Method Reference

The following methods are available on EdgesArray objects. This reference is generated from comprehensive API testing and shows all empirically validated methods.

Method Returns Status
contains() ?
filter() ?
filter_by_size() EdgesArray
filter_by_weight() EdgesArray
first() EdgesAccessor
interactive() ?
is_empty() bool
iter() EdgesArrayIterator
last() EdgesAccessor
nodes() NodesArray
stats() dict
table() TableArray
to_list() list
total_edge_count() int
union() EdgesAccessor

Legend: - ✓ = Method tested and working - ✗ = Method failed in testing or not yet validated - ? = Return type not yet determined


Detailed Method Reference

Creating EdgesArray

EdgesArray is typically returned from edge grouping operations:

import groggy as gr

g = gr.generators.karate_club()

# From edge grouping
by_type = g.edges.group_by("type")  # → EdgesArray
print(type(by_type))  # EdgesArray

# Each element is an EdgesAccessor (edge collection)
for edges in by_type:
    print(f"{edges.edge_count()} edges in group")

Key Concept: EdgesArray is an array of edge collections, where each element is an EdgesAccessor representing a group of edges.


Core Methods

first()

Get first edge collection.

Returns: - EdgesAccessor: First group of edges

Example:

by_type = g.edges.group_by("type")
first_group = by_type.first()
print(f"First group: {first_group.edge_count()} edges")

Performance: O(1)


last()

Get last edge collection.

Returns: - EdgesAccessor: Last group of edges

Example:

by_type = g.edges.group_by("type")
last_group = by_type.last()
print(f"Last group: {last_group.edge_count()} edges")

Performance: O(1)


is_empty()

Check if array has no groups.

Returns: - bool: True if no groups

Example:

by_type = g.edges.group_by("type")
if by_type.is_empty():
    print("No groups found")
else:
    print(f"{len(by_type)} edge groups")

Performance: O(1)


iter()

Iterate over edge collections.

Returns: - Iterator over EdgesAccessor objects

Example:

by_type = g.edges.group_by("type")

for edges_group in by_type.iter():
    print(f"Group: {edges_group.edge_count()} edges")
    # Access attributes
    if edges_group.edge_count() > 0:
        weights = edges_group["weight"]
        print(f"  Avg weight: {weights.mean():.2f}")

Performance: O(1) per iteration


Aggregation Methods

total_edge_count()

Get total edges across all groups.

Returns: - int: Total edge count

Example:

by_type = g.edges.group_by("type")
total = by_type.total_edge_count()
print(f"Total edges: {total}")

# Should equal original graph
assert total == g.edge_count()

Performance: O(k) where k is number of groups


union()

Combine all edge groups into single collection.

Returns: - EdgesAccessor: Union of all groups

Example:

by_type = g.edges.group_by("type")
all_edges = by_type.union()

# Should contain all edges
print(f"Union: {all_edges.edge_count()} edges")
assert all_edges.edge_count() == g.edge_count()

Performance: O(k) where k is number of groups


stats()

Get statistics about the array.

Returns: - dict: Statistics including group count, sizes, etc.

Example:

by_type = g.edges.group_by("type")
stats = by_type.stats()
print(stats)
# {'num_groups': 3, 'total_edges': 78, 'avg_size': 26.0, ...}


Filtering Methods

filter_by_size(min_size, max_size=None)

Filter groups by edge count.

Parameters: - min_size (int): Minimum edges in group - max_size (int, optional): Maximum edges in group

Returns: - EdgesArray: Filtered array

Example:

by_type = g.edges.group_by("type")

# Only large groups
large = by_type.filter_by_size(min_size=10)
print(f"{len(large)} groups with ≥10 edges")

# Size range
medium = by_type.filter_by_size(min_size=5, max_size=20)

Performance: O(k) where k is number of groups


filter_by_weight(threshold, operator='>')

Filter groups by average weight.

Parameters: - threshold (float): Weight threshold - operator (str): Comparison operator ('>', '<', '>=', '<=', '==')

Returns: - EdgesArray: Filtered array

Example:

by_type = g.edges.group_by("type")

# Groups with high average weight
heavy = by_type.filter_by_weight(threshold=5.0, operator='>')
print(f"{len(heavy)} groups with avg weight > 5.0")

# Groups with low average weight
light = by_type.filter_by_weight(threshold=2.0, operator='<')


Conversion Methods

to_list()

Convert to Python list of EdgesAccessor objects.

Returns: - list[EdgesAccessor]: List of edge groups

Example:

by_type = g.edges.group_by("type")
groups = by_type.to_list()

for i, group in enumerate(groups):
    print(f"Group {i}: {group.edge_count()} edges")

Performance: O(k) where k is number of groups


table()

Convert all groups to table array.

Returns: - TableArray: Array of tables, one per group

Example:

by_type = g.edges.group_by("type")
tables = by_type.table()

# Export each group
for i, tbl in enumerate(tables):
    tbl.to_csv(f"edge_group_{i}.csv")


nodes()

Get node groups corresponding to edge groups.

Returns: - NodesArray: Array of node collections (endpoints)

Example:

by_type = g.edges.group_by("type")
node_groups = by_type.nodes()

# Analyze nodes involved in each edge type
for i, nodes in enumerate(node_groups):
    print(f"Type {i}: {nodes.node_count()} nodes involved")

Notes: Returns nodes that are endpoints of edges in each group


Additional Methods

contains(item)

Check if array contains specific item.

Parameters: - item: Item to check for

Returns: - bool: True if item exists

Example:

by_type = g.edges.group_by("type")
if by_type.contains(some_group):
    print("Group found")

Status: Requires item parameter


filter(predicate)

Filter groups by predicate function.

Parameters: - predicate: Filter function

Returns: - EdgesArray: Filtered array

Example:

by_type = g.edges.group_by("type")
large = by_type.filter(lambda g: g.edge_count() > 10)

Status: Requires predicate parameter


interactive()

Launch interactive visualization (not yet implemented).

Returns: - str: HTML/visualization output

Example:

by_type = g.edges.group_by("type")
# Not yet implemented - use workaround:
by_type.table().interactive_viz()

Status: Not yet implemented - use .table().interactive_viz() instead


Indexing & Slicing

EdgesArray supports indexing and slicing:

Example:

by_type = g.edges.group_by("type")

# Get specific group
group_0 = by_type[0]  # First group (EdgesAccessor)
print(f"Group 0: {group_0.edge_count()} edges")

# Slice
first_three = by_type[:3]  # First 3 groups (EdgesArray)

# Negative indexing
last_group = by_type[-1]


Usage Patterns

Pattern 1: Edge Type Analysis

by_type = g.edges.group_by("type")

print(f"Total edge types: {len(by_type)}")
print(f"Total edges: {by_type.total_edge_count()}")

for i, edges_group in enumerate(by_type):
    weights = edges_group["weight"]
    print(f"\nType {i}:")
    print(f"  Count: {edges_group.edge_count()}")
    print(f"  Avg weight: {weights.mean():.2f}")
    print(f"  Weight range: {weights.min():.1f}-{weights.max():.1f}")

Pattern 2: Filter and Analyze

by_type = g.edges.group_by("type")

# Only significant edge types (≥10 edges)
significant = by_type.filter_by_size(min_size=10)

for edges in significant:
    edge_type = edges["type"].first()
    print(f"\n{edge_type}:")
    print(f"  Edges: {edges.edge_count()}")

    # Analyze endpoint nodes
    nodes = edges.nodes()
    print(f"  Nodes involved: {nodes.node_count()}")
    print(f"  Avg degree: {nodes.degree().mean():.2f}")

Pattern 3: Weight-Based Filtering

by_type = g.edges.group_by("type")

# Heavy edge types
heavy_types = by_type.filter_by_weight(threshold=5.0, operator='>')

print(f"{len(heavy_types)} heavy edge types:")
for edges in heavy_types:
    edge_type = edges["type"].first()
    weights = edges["weight"]
    print(f"  {edge_type}: avg={weights.mean():.2f}, max={weights.max():.2f}")

Pattern 4: Export by Type

by_type = g.edges.group_by("type")

# Export each edge type separately
for i, edges_group in enumerate(by_type):
    edge_type = edges_group["type"].first() if edges_group.edge_count() > 0 else f"type_{i}"

    # Create edge list
    df = edges_group.table().to_pandas()
    df.to_csv(f"edges_{edge_type}.csv", index=False)

    print(f"Exported {edge_type}: {len(df)} edges")

Pattern 5: Cross-Type Comparison

by_type = g.edges.group_by("type")

groups = by_type.to_list()
if len(groups) >= 2:
    type_a = groups[0]
    type_b = groups[1]

    print("Type comparison:")
    print(f"  Type A: {type_a.edge_count()} edges")
    print(f"    Avg weight: {type_a['weight'].mean():.2f}")
    print(f"    Nodes: {type_a.nodes().node_count()}")

    print(f"  Type B: {type_b.edge_count()} edges")
    print(f"    Avg weight: {type_b['weight'].mean():.2f}")
    print(f"    Nodes: {type_b.nodes().node_count()}")

Pattern 6: Hierarchical Edge Analysis

# Group by primary type
by_primary = g.edges.group_by("primary_type")

for primary_edges in by_primary:
    primary = primary_edges["primary_type"].first()
    print(f"\n{primary}:")

    # Sub-group by secondary type
    by_secondary = primary_edges.group_by("secondary_type")
    for secondary_edges in by_secondary:
        secondary = secondary_edges["secondary_type"].first()
        print(f"  {secondary}: {secondary_edges.edge_count()} edges")

Quick Reference

Method Returns Description
first() EdgesAccessor First group
last() EdgesAccessor Last group
is_empty() bool Check if empty
iter() Iterator Iterate groups
total_edge_count() int Total edges
union() EdgesAccessor Combine all groups
stats() dict Array statistics
filter_by_size(min, max) EdgesArray Filter by edge count
filter_by_weight(thresh, op) EdgesArray Filter by avg weight
to_list() list Convert to list
table() TableArray Convert to tables
nodes() NodesArray Get endpoint nodes
[i] EdgesAccessor Get group by index
[:n] EdgesArray Slice groups

Object Transformations

EdgesArray can transform into:

  • EdgesArray → Subgraph: g.edges[edge_array]
  • EdgesArray → ndarray: edge_array.to_numpy()

See Object Transformation Graph for complete delegation chains.


See Also