BUILT-IN MATHEMATICA SYMBOL

EdgeQ

yields True if e is an edge in the graph g and False otherwise.

EXAMPLES

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Basic Examples (2)

Test whether undirected edges are part of a graph:

Test directed edges:

Test whether undirected edges are part of a graph:

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Test directed edges:

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Scope (6)

EdgeQ works with undirected graphs:

Directed graphs:

EdgeQ returns False for items that are not edge expressions:

Rules can be used to test for directed edges:

When g is not a graph, EdgeQ

evaluates to False:

Verify that g is not a graph using GraphQ:

EdgeQ works with large graphs:

Compare performance with a test based on EdgeList:

Applications (3)

Test whether

is adjacent to

:

Check input to a function:

Take correct action depending on whether an item is an edge or a vertex:

Act on an edge:

Act on a vertex:

Properties & Relations (4)

EdgeQ

is equivalent to MemberQ[EdgeList[g], u

v]:

The performance of EdgeQ is typically higher:

EdgeQ

is equivalent to MemberQ[EdgeList[g], u

v|v

u]:

The performance of EdgeQ is typically higher:

Use EdgeIndex to find the position of an edge in EdgeList[g]:

EdgeIndex is typically faster than Position:

Use VertexQ to test whether a vertex is part of a graph:

Possible Issues (1)

Some edges do not seem to be recognized:

Membership is tested using SameQ rather than Equal:

By using identical expressions it can still be tested: