term.labels() extracts term labels from a fitted model object or a character vector.
Its primary strength is the ability to filter terms based on their order or their associated underlying variables.
Usage
term.labels(object, ...)
# Default S3 method
term.labels(object, order = NULL, require = NULL, remove = NULL, ...)
# S3 method for class 'midlist'
term.labels(object, ...)Arguments
- object
an object containing model terms (such as a "lm", "glm", or "mid" object) or term labels directly, a "terms" object, or a character vector of term labels.
- ...
not used.
- order
an integer vector specifying the order of terms to retain (e.g.,
1for only main effects,2for only two-way interactions).- require
a character vector of variable names. If provided, only terms containing at least one of these variables are returned.
- remove
a character vector of variable names. If provided, terms containing any of these variables are completely excluded.
Details
A "term" refers to an individual component in a formula, such as a main effect (e.g., "Wind") or an interaction effect (e.g., "Wind:Temp").
This function safely parses the model's terms and provides a flexible way to select a subset of them, which is especially useful for plotting, summarizing, or other downstream analyses.
Examples
data(airquality, package = "datasets")
mid <- interpret(Ozone ~ .^2, airquality, lambda = 1)
#> 'model' not passed: response variable in 'data' is used
# Get only main effect terms
term.labels(mid, order = 1)
#> [1] "Solar.R" "Wind" "Temp" "Month" "Day"
# Get terms related to "Wind" or "Temp"
term.labels(mid, require = c("Wind", "Temp"))
#> [1] "Wind" "Temp" "Solar.R:Wind" "Solar.R:Temp" "Wind:Temp"
#> [6] "Wind:Month" "Wind:Day" "Temp:Month" "Temp:Day"
# Get terms related to "Wind" or "Temp", but exclude any with "Day"
term.labels(mid, require = c("Wind", "Temp"), remove = "Day")
#> [1] "Wind" "Temp" "Solar.R:Wind" "Solar.R:Temp" "Wind:Temp"
#> [6] "Wind:Month" "Temp:Month"