Set operations
Performs set union, intersection and (asymmetric!) difference on two vector-like objects.
NOTE: This man page is for the union, intersect and
setdiff S4 generic functions defined in the BiocGenerics
package.
See ?base::union for the default methods
(defined in the base package).
Bioconductor packages can define specific methods for objects
(typically vector-like) not supported by the default methods.
union(x, y, ...) intersect(x, y, ...) setdiff(x, y, ...)
x, y |
Vector-like objects (typically of the same class, but not necessarily). |
... |
Additional arguments, for use in specific methods. |
See ?base::union for the value returned by the
default methods.
Specific methods defined in Bioconductor packages will typically return an object of the same class as the input objects.
The default methods (defined in the base package) only take 2
arguments. We've added the ... argument to the generic functions
defined in the BiocGenerics package so they can be called with an
arbitrary number of effective arguments.
For union or intersect, this typically allows Bioconductor
packages to define methods that compute the union or intersection of more
than 2 objects. However, for setdiff, which is conceptually a
binary operation, this typically allows methods to add extra arguments
for controlling/altering the behavior of the operation.
Like for example the ignore.strand argument supported by the
setdiff method for GenomicRanges objects
(defined in the GenomicRanges package). (Note that the union
and intersect methods for those objects also support the
ignore.strand argument.)
base::union for the default union,
intersect, and setdiff methods.
showMethods for displaying a summary of the
methods defined for a given generic function.
selectMethod for getting the definition of
a specific method.
union,GenomicRanges,GenomicRanges-method in
the GenomicRanges package for examples of specific
union, intersect, and setdiff methods (defined
for GenomicRanges objects).
BiocGenerics for a summary of all the generics defined in the BiocGenerics package.
union
showMethods("union")
selectMethod("union", c("ANY", "ANY")) # the default method
intersect
showMethods("intersect")
selectMethod("intersect", c("ANY", "ANY")) # the default method
setdiff
showMethods("setdiff")
selectMethod("setdiff", c("ANY", "ANY")) # the default methodPlease choose more modern alternatives, such as Google Chrome or Mozilla Firefox.