Combine design steps into a design

The + operator concatenates design_step and design objects into a single design. design + NULL is a no-op that returns the design unchanged, which makes conditional step addition convenient.

Usage

# S3 method for class 'dd'
e1 + e2

Arguments

e1

(required) A design_step, a design, or NULL.

e2

(required) A design_step, a design, or NULL.

Value

A design (class c("design", "dd")): a list of the steps of e1 followed by those of e2, named by their labels.

Examples

d <- declare_model(N = 50, U = rnorm(N), Y = U) +
  declare_inquiry(mu = mean(Y))
length(d)
#> [1] 2