ergm (version 3.9.4)

node-attr-api: Helper functions for specifying nodal attribute levels

Description

These functions are meant to be used in InitErgmTerm and other implementations to provide the user with a way to extract nodal attributes and select their levels in standardized and flexible ways described under node-attr.

ergm_get_vattr extracts and processes the specified nodal attribute vector. It is strongly recommended that check.ErgmTerm()'s corresponding vartype="function,formula,character" (using the ERGM_VATTR_SPEC constant).

ergm_attr_levels filters the levels of the attribute. It is strongly recommended that check.ErgmTerm()'s corresponding vartype="function,formula,character,numeric,logical,AsIs,NULL" (using the ERGM_LEVELS_SPEC constant).

Usage

ergm_get_vattr(object, nw, accept = "character", bip = c("n", "b1",
  "b2"), ...)
# S3 method for character
ergm_get_vattr(object, nw, accept = "character",
  bip = c("n", "b1", "b2"), ...)
# S3 method for function
ergm_get_vattr(object, nw, accept = "character",
  bip = c("n", "b1", "b2"), ...)
# S3 method for formula
ergm_get_vattr(object, nw, accept = "character",
  bip = c("n", "b1", "b2"), ...)
ergm_attr_levels(object, attr, nw, levels = sort(unique(attr)), ...)
# S3 method for numeric
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for logical
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for AsIs
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for character
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for NULL
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for function
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
# S3 method for formula
ergm_attr_levels(object, attr, nw,
  levels = sort(unique(attr)), ...)
ERGM_VATTR_SPEC
ERGM_LEVELS_SPEC

Arguments

object

An argument specifying the nodal attribute to select or which levels to include.

nw

Network on the LHS of the formula.

accept

A character vector listing permitted data types for the output. See the Details section for the specification.

bip

Bipartedness mode: affects either length of attribute vector returned or the length permited: "n" for full network, "b1" for first mode of a bipartite network, and "b2" for the second.

...

Additional argument to the functions of network or to the formula's environment.

attr

A vector of length equal to the number of nodes, specifying the attribute vector.

levels

Starting set of levels to use; defaults to the sorted list of unique attributes.

Value

ergm_get_vattr returns a vector of length equal to the number of nodes giving the selected attribute function. It may also have an attribute "name", which controls the suggested name of the attribute combination.

ergm_attr_levels returns a vector of levels to use and their order.

Format

An object of class character of length 1.

Details

The accept argument is meant to allow the user to quickly check whether the output is of an acceptable class or mode. Typically, if a term accepts a character (i.e., categorical) attribute, it will also accept a numeric one, treating each number as a category label. For this reason, the following outputs are defined:

"character"

Accept any mode or class (since it can beconverted to character).

"numeric"

Accept real, integer, or logical.

"logical"

Accept logical.

"integer"

Accept integer or logical.

"natural"

Accept a strictly positive integer.

"0natural"

Accept a nonnegative integer or logical.

"nonnegative"

Accept a nonnegative number or logical.

"positive"

Accept a strictly positive number or logical.

Examples

# NOT RUN {
data(florentine)
ergm_get_vattr("priorates", flomarriage)
ergm_get_vattr(~priorates, flomarriage)
ergm_get_vattr(c("wealth","priorates"), flomarriage)
ergm_get_vattr(~priorates>30, flomarriage)
(a <- ergm_get_vattr(~cut(priorates,c(-Inf,0,20,40,60,Inf),label=FALSE)-1, flomarriage))
ergm_attr_levels(NULL, a, flomarriage)
ergm_attr_levels(-1, a, flomarriage)
ergm_attr_levels(1:2, a, flomarriage)
ergm_attr_levels(I(1:2), a, flomarriage)
# }