[function]
Function to apply. Rows are passed as list or vector,
depending on argument unlist, as first argument.
...
[ANY]
Additional arguments for fun.
unlist
[logical(1)]
Unlist the row? Note that automatic conversion may be triggered for
lists of mixed data types
Default is FALSE.
simplify
[logical(1) | character(1)]
Should the result be simplified?
See sapply.
If cols, we expect the call results to be vectors of the same length and they are
arranged as the columns of the resulting matrix.
If rows, likewise, but rows of the resulting matrix.
Default is TRUE.
use.names
[logical(1)]
Should result be named by the row names of df?
Default is TRUE.