This function select objects by their position specified by index.
Usage
selectByIndex(index, ...)
Arguments
index
a numeric value or vector specifying position.
...
an arbitrary number of objects to be selected.
Value
a selected object or a list of selected objects.
Details
This function select object by their position specified by index. When index is vector, a list of selected objects is returned. Main use of this function is to select time-specific covariate with getIndex function.