Used internally. Helpers for simplifying code invoking vapply().
vapply_num(X, FUN, ...)vapply_int(X, FUN, ...)
vapply_str(X, FUN, ...)
vapply_lgl(X, FUN, ...)
a vector (atomic or list) or an expression
object. Other objects (including classed objects) will be coerced
by base::as.list.
the function to be applied to each element of X:
see ‘Details’. In the case of functions like
+, %*%, the function name must be backquoted or quoted.
optional arguments to FUN.