Function constructor for injecting "missing together" NAs to columns

This constructor creates a function which will set all nvars columns to NA together for rows selected for missing data.

miss_as_block(p, nvars)

Arguments

p	numeric(1). Proportion of observations to change to missing
nvars	numeric(1). Number of columns this behavior should be applied to.

Value

a function suitable for use in missingness recipe, which when given .df, the data will return an N x nvars logical matrix.