Declare a sampling procedure

Draws the sample from the population, keeping the rows where the sampling indicator S is 1. Name the indicator S, as in declare_sampling(S = complete_rs(N, n = 50)), or say which rows to keep with filter = ; a sampling step that produces neither keeps every row and warns.

Usage

declare_sampling(..., filter = NULL, label = "sampling", draws = 1L)

Arguments

...

(optional) Named arguments forwarded to fabricatr::fabricate(). Unquoted expressions are evaluated lazily in the caller's environment with access to the current data frame.

filter

(optional) Unquoted expression evaluated against the data; rows where the expression is TRUE are retained, and S is then not consulted.

label

(optional) Step label. Defaults to "sampling".

draws

(optional) Number of nested draws for this step. Defaults to 1. When > 1, the step is re-executed draws times for each upstream draw during nested simulation.

Value

A design_step (class c("design_step", "dd", "function")): a function that takes the current data frame and returns the rows sampled, with any declared columns added. Add it to a design with +.

See also

Other design declarations: declare_assignment(), declare_estimator(), declare_inquiry(), declare_measurement(), declare_model(), declare_notes(), declare_parameters(), declare_step(), declare_test()

Examples

design <-
  declare_model(N = 200, Y = rnorm(N)) +
  declare_sampling(S = sample(rep(0:1, length.out = N)))

nrow(draw_data(design))
#> [1] 100