Nest a level in the one before it (same as a later add_level())

For each row in the current data frame, creates N child rows. This is what add_level does after the first level of a call; nest_level() is the spelling that says so. Parent columns are replicated across children. N may be a scalar (same count for every parent) or a vector of length nrow of the parent (variable children per parent).

Usage

nest_level(N, ...)

Arguments

N

Rows per parent. Scalar or per-parent vector.

...

Column expressions. Note that the N visible inside these expressions is the total number of rows the level creates, not the per-parent count in the N argument: nesting 5 citizens in each of 20 villages makes N equal to 100 here. The behaviour matches fabricatr 1.x, and it is what makes rnorm(N) draw independently for every village rather than drawing five values and reusing them.

Value

A fabricatr_level object, meaningful only as a named argument to fabricate. It replaces each row of the current frame with N child rows, repeating the parent's columns down them, and adds an ID column named after the argument it is assigned to. That ID is unique across the whole frame rather than restarting within each parent.

Examples

fabricate(
  villages = add_level(N = 20, v_income = rnorm(N)),
  citizens = nest_level(N = 5, income = v_income + rnorm(N))
)
#> # A tibble: 100 × 4
#>    villages v_income citizens  income
#>    <chr>       <dbl> <chr>      <dbl>
#>  1 01         0.0180 001       0.0281
#>  2 01         0.0180 002      -0.659 
#>  3 01         0.0180 003      -0.540 
#>  4 01         0.0180 004      -0.329 
#>  5 01         0.0180 005       1.39  
#>  6 02        -0.872  006      -0.960 
#>  7 02        -0.872  007      -1.98  
#>  8 02        -0.872  008      -1.09  
#>  9 02        -0.872  009      -0.384 
#> 10 02        -0.872  010      -0.838 
#> # ℹ 90 more rows