isNested function

Is f1 nested within f2?

Does every level of f1 occur in conjunction with exactly one level of f2? The function is based on converting a triplet sparse matrix to a compressed column-oriented form in which the nesting can be quickly evaluated.

isNested(f1, f2)

Arguments

• f1: factor 1
• f2: factor 2

Returns

TRUE if factor 1 is nested within factor 2

Examples

library(lme4)
  with(Pastes, isNested(cask, batch))   ## => FALSE
  with(Pastes, isNested(sample, batch))  ## => TRUE