The XDoubleViews class
The XDoubleViews class is the basic container for storing a set of views (start/end locations) on the same XDouble object.
An XDoubleViews object contains a set of views (start/end locations) on the
same XDouble object called "the subject numeric vector" or simply
"the subject".
Each view is defined by its start and end locations: both are integers such
that start <= end.
An XDoubleViews object is in fact a particular case of a
Views object (the XDoubleViews class contains the
Views class) so it can be manipulated in a similar manner:
see ?Views for more information.
Note that two views can overlap and that a view can be "out of limits"
i.e. it can start before the first element of the subject or/and end
after its last element.
In the code snippets below,
x, object, e1 and e2 are XDoubleViews objects,
and i can be a numeric or logical vector.
x[[i]]:
Extract a view as an XDouble object.
i must be a single numeric value (a numeric vector of length 1).
Can't be used for extracting a view that is "out of limits" (raise an
error). The returned object has the same XDouble subtype as
subject(x).
e1 == e2:
A vector of logicals indicating the result of the view by
view comparison. The views in the shorter of the two XDoubleViews
object being compared are recycled as necessary.
e1 != e2:
Equivalent to !(e1 == e2).
P. Aboyoun for the XIntegerViews* code, which was adapted to work
over XDouble's by S. Lianoglou
## One standard way to create an XDoubleViews object is to use
## the Views() constructor:
subject <- as(rnorm(6), "XDouble")
v4 <- Views(subject, start=3:0, end=5:8)
v4
subject(v4)
length(v4)
start(v4)
end(v4)
width(v4)
## Attach a comment to views #3 and #4:
names(v4)[3:4] <- "out of limits"
names(v4)
## A more programatical way to "tag" the "out of limits" views:
idx <- start(v4) < 1 | end(v4) > length(subject(v4))
names(v4)[idx] <- "out of limits"
## Extract a view as an XDouble object:
v4[[2]]
## It is an error to try to extract an "out of limits" view:
## Not run:
v4[[3]] # Error!
## End(Not run)
## Here the first view doesn't even overlap with the subject:
subject <- as(c(97, 97, 97, 45, 45, 98), "XDouble")
Views(subject, start=-3:4, end=-3:4 + c(3:6, 6:3))
## Some fast view* functionalities:
x <- rnorm(55)
bounds <- IRanges(c(1, 11, 35, 20), width=c(5, 10, 15, 28))
v <- Views(x, bounds)
val <- viewMins(v)
expect <- sapply(1:length(bounds), function(i) {
min(x[start(bounds)[i]:end(bounds[i])])
})
stopifnot(all(val == expect))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.