Skip to contents

Create ego network from a netify object

Source: R/ego_netify.R
ego_netify.Rd

ego_netify extracts an ego network from a netify object. An ego network consists of a focal node (ego) and its immediate neighbors (alters). For weighted networks, users can define neighborhoods using edge weight thresholds. The function returns a netify object representing the ego network.

Usage

ego_netify(
  netlet,
  ego,
  threshold = NULL,
  ngbd_direction = "any",
  include_ego = TRUE
)

Arguments

netlet

A netify object (class "netify") from which to extract the ego network.

ego

Character string specifying the name of the ego for whom to create the ego network. Must match an actor name in the netify object.

threshold

Numeric value or vector specifying the threshold for including alters in the ego network based on edge weights. For longitudinal networks, can be a vector with length equal to the number of time periods to apply different thresholds over time. If NULL (default), uses 0 for unweighted networks and the mean edge weight for weighted networks.

ngbd_direction

Character string specifying which neighbors to include for directed networks. Options are:

  • "out": Include alters that ego has outgoing ties to

  • "in": Include alters that ego has incoming ties from

  • "any": Include alters with any tie to/from ego (default)

include_ego

Logical. If TRUE (default), the ego node is included in the ego network. If FALSE, only alters are included.

Value

A netify object representing the ego network. For longitudinal networks, returns a list of netify objects with one ego network per time period.

Each returned netify object includes additional attributes:

  • ego_netify: TRUE (indicator that this is an ego network)

  • ego_id: Identifier of the ego

  • threshold: Threshold value(s) used

  • ngbd_direction: Direction specification used

  • include_ego: Whether ego was included

Details

The function extracts an ego network by identifying all nodes connected to the specified ego based on the given criteria:

Neighborhood definition:

  • For unweighted networks: All nodes with edges to/from ego (threshold = 0)

  • For weighted networks: All nodes with edge weights exceeding the threshold

  • Direction matters only for directed networks (controlled by ngbd_direction)

Threshold behavior:

  • If not specified, defaults to 0 for unweighted networks

  • If not specified for weighted networks, uses the mean edge weight

  • For longitudinal networks, can vary by time period if a vector is provided

  • Edges with weights > threshold are included (not ≥)

Output structure:

The function preserves all attributes from the original netify object, including nodal and dyadic variables, but subsets them to include only ego and its neighbors. For longitudinal networks, ego networks may vary in composition across time periods as relationships change.

Limitations:

  • Currently does not support multilayer networks

  • Currently does not support bipartite networks

Note

To create ego networks for multiple egos, use lapply or a loop to call this function for each ego separately.

Author

Cassy Dorff, Shahryar Minhas