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Create a netify list from longitudinal dyadic data

Source: R/get_adjacency_list.R
get_adjacency_list.Rd

get_adjacency_list converts longitudinal dyadic data into a list of adjacency matrices of class "netify". This function creates a list structure where each element is a network matrix for a specific time period, allowing for time-varying actor composition.

Usage

get_adjacency_list(
  dyad_data,
  actor1 = NULL,
  actor2 = NULL,
  time = NULL,
  symmetric = TRUE,
  mode = "unipartite",
  weight = NULL,
  sum_dyads = FALSE,
  actor_time_uniform = FALSE,
  actor_pds = NULL,
  diag_to_NA = TRUE,
  missing_to_zero = TRUE,
  nodelist = NULL
)

Arguments

dyad_data

A data.frame containing longitudinal dyadic observations. Will be coerced to data.frame if a tibble or data.table is provided.

actor1

Character string specifying the column name for the first actor in each dyad.

actor2

Character string specifying the column name for the second actor in each dyad.

time

Character string specifying the column name for time periods.

symmetric

Logical. If TRUE (default), treats the network as undirected (i.e., edges have no direction). If FALSE, treats the network as directed.

mode

Character string specifying network structure. Options are:

  • "unipartite": One set of actors (default)

  • "bipartite": Two distinct sets of actors

weight

Character string specifying the column name containing edge weights. If NULL (default), edges are treated as unweighted (binary).

sum_dyads

Logical. If TRUE, sums weight values when multiple edges exist between the same actor pair in the same time period. If FALSE (default), uses the last observed value.

actor_time_uniform

Logical indicating how to handle actor composition:

  • TRUE: Assumes all actors exist across the entire time range

  • FALSE: Determines actor existence from the data - actors exist from their first observed interaction to their last

actor_pds

Optional data.frame specifying when actors enter and exit the network. Must contain columns 'actor', 'min_time', and 'max_time'. Can be created using get_actor_time_info(). If provided, overrides actor_time_uniform.

diag_to_NA

Logical. If TRUE (default), sets diagonal values (self-loops) to NA. Automatically set to FALSE for bipartite networks.

missing_to_zero

Logical. If TRUE (default), treats missing edges as zeros. If FALSE, missing edges remain as NA.

nodelist

Character vector of actor names to include in the network. If provided, ensures all listed actors appear in the network even if they have no edges (isolates). Useful when working with edgelists that only contain active dyads.

Value

A list of class "netify" (a netify list) with:

  • Elements: Named list where each element is a netify matrix for one time period

  • Names: Character representation of time periods

  • Class: "netify" - this is a full netify object compatible with all netify functions

  • Attributes: Extensive metadata including network properties, actor composition information, and processing parameters

Each matrix in the list may have different dimensions if actor composition varies over time. The returned object can be used with all netify functions such as summary(), plot(), to_igraph(), etc.

Details

Note on usage:

While this function is exported and available for direct use, the primary and recommended way to create netify objects from longitudinal dyadic data is through the netify() function. The netify() function:

  • Automatically chooses between array and list representations based on your data

  • Provides more comprehensive data validation

  • Can incorporate nodal and dyadic attributes during creation

  • Offers a unified interface for all types of network data

Use get_adjacency_list() directly only when you specifically need a list structure or require low-level control over the creation process.

Actor composition handling:

This function is particularly useful when actors enter and exit the network over time. Unlike get_adjacency_array(), which requires constant actor composition, this function can handle:

  • New actors appearing in later time periods

  • Actors exiting and no longer appearing in the data

  • Different sets of actors active in each time period

Author

Cassy Dorff, Ha Eun Choi, Shahryar Minhas

Examples

# Load example data
data(icews)

# Create a netify list with constant actor composition
icews_list <- get_adjacency_list(
    dyad_data = icews,
    actor1 = "i",
    actor2 = "j",
    time = "year",
    actor_time_uniform = TRUE,
    symmetric = FALSE,
    weight = "verbConf"
)

# Verify it's a netify object
class(icews_list) # "netify"
#> [1] "netify"

# Check structure
length(icews_list) # Number of time periods
#> [1] 13
names(icews_list) # Time period labels
#>  [1] "2002" "2003" "2004" "2005" "2006" "2007" "2008" "2009" "2010" "2011"
#> [11] "2012" "2013" "2014"

# Access specific time period
icews_2010 <- icews_list[["2010"]]
dim(icews_2010)
#> [1] 152 152