Head Step

The head step navigates from edges to their target (destination) vertices, allowing traversal to where the edges point to. It transforms a stream of edges into a stream of vertices.

In this diagram:

An Input Stream contains edge elements (e.g., A->B, C->D).
The .head() step processes each edge.
The Output Stream contains the corresponding target (head) vertices (B, D) for each input edge.

Syntax

walker.head()

Parameters

This step takes no parameters.

Return Value

Returns a new walker positioned at the target vertices of the edges in the current traversal.

Example

Find projects created by people known by a starting person:

    // Find the projects created by people followed by the starting person
    let projects: Vec<_> = graph
        .walk()
        .vertices_by_id([start_person_id]) // Start at a specific person
        .edges(EdgeSearch::scan().outgoing()) // Follow outgoing edges
        .filter_follows() // Keep only 'Follows' edges
        .head() // Move to the target vertices (people followed by the start person)
        .edges(EdgeSearch::scan().outgoing()) // Follow outgoing edges from these people
        .filter_created() // Keep only 'Created' edges
        .head() // Move to the target vertices (projects created by known people)
        .collect();

    println!(
        "Projects created by people followed by the starting person ({:?}):",
        projects
    );

Best Practices

Use head() to follow relationships in their natural direction (to the target).
Chain edge-head sequences for multi-hop traversals towards targets.
Maintain context information when necessary to preserve edge properties while moving to the target.
Consider traversal depth carefully in highly connected graphs when following edges.

Common Use Cases

Following relationships: Finding what vertices are connected to your starting points (targets).
Multi-hop traversals: Discovering indirect connections through multiple relationships towards targets.
Graph exploration: Navigating through the graph in a directed manner towards targets.
Social network queries: Implementing patterns like "friends of friends" or "recommendations" by moving to targets.

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