lapply and sapply with indexImprove base::lapply() and base::sapply() functions by allowing
an extra index argument .I to be passed into the function given in FUN.
If the function given in FUN has an argument .I then, for each entry
of X passed into FUN the corresponding index is passed into
argument .I. If the function given in FUN has no argument .I,
then lapplI and sapplI are exactly the same as
base::lapply() and base::sapply().
Besides this extra feature, there is no difference to base::lapply() and
base::sapply().
lapplI(X, FUN, ...)sapplI(X, FUN, ..., simplify = TRUE, USE.NAMES = TRUE)
a vector (atomic or list) or an expression
object. Other objects (including classed objects) will be coerced
by base::as.list.
Here comes the great difference to base::lapply() and
base::sapply(). When using lapplI and sapplI, the function
passed into FUN may also have an extra argument .I. If it does, then
for each item of X the current item index
is passed into argument .I of FUN.
Besides this extra feature, there is no difference to base::lapply() and
base::sapply().
optional arguments to FUN.
logical or character string; should the result be
simplified to a vector, matrix or higher dimensional array if
possible? For sapply it must be named and not abbreviated.
The default value, TRUE, returns a vector or matrix if appropriate,
whereas if simplify = "array" the result may be an
array of “rank”
(\(=\)length(dim(.))) one higher than the result
of FUN(X[[i]]).
logical; if TRUE and if X is character,
use X as names for the result unless it had names
already. Since this argument follows … its name cannot
be abbreviated.