dot-warn_if_onelevel function

Warn if one level factor

Factors with only one level happen if a character vector is converted to a factor using factor() but without specifying anything for the levels

parameter. If you try to access or set the contrasts for a one-level factor, you'll get an error that contrasts are undefined because you have 0 degrees of freedom.

.warn_if_onelevel(
  one_level_factors = NULL,
  model_data = NULL,
  attempting_factors = NULL
)

Arguments

• one_level_factors: Character vector of which factors are one level
• model_data: Model data to look for factor columns
• attempting_factors: Factor column names to check

Returns

Nothing, warns if factors with only one level are detected.