Check if an object contains more than one unique value
is_constant(x, na.rm = FALSE)Vector or matrix.
Whether to ignore missing values.
Logical scalar that is TRUE if x contains more than one
unique value and FALSE if not.
A logical scalar that is TRUE if x contains more than
one unique value and FALSE otherwise. In case x contains
missing values NA is returned if na_rm = FALSE. If there are
no non-missing values NA is always returned.