Negation of in
x %notin% y
| x | Values to be matched |
|---|---|
| y | Values to be matched against. |
If y is NULL, then x is TRUE for consistency with
%in%. Note that the function uses fmatch internally for
performance on large y. Accordingly, y will be modified by adding
a .match.hash attribute and thus must not be used in packages where y
is a constant, or for things like names of data.table.