Hybrid Index, coercion to
as.hi(x, ...) ## S3 method for class 'NULL' as.hi(x, ...) ## S3 method for class 'hi' as.hi(x, ...) ## S3 method for class 'ri' as.hi(x, maxindex = length(x), ...) ## S3 method for class 'bit' as.hi(x, range = NULL, maxindex = length(x), vw = NULL , dim = NULL, dimorder = NULL, pack = TRUE, ...) ## S3 method for class 'bitwhich' as.hi(x, maxindex = length(x), pack = FALSE, ...) ## S3 method for class 'call' as.hi(x, maxindex = NA, dim = NULL, dimorder = NULL, vw = NULL , vw.convert = TRUE, pack = TRUE, envir = parent.frame(), ...) ## S3 method for class 'name' as.hi(x, envir = parent.frame(), ...) ## S3 method for class 'integer' as.hi(x, maxindex = NA, dim = NULL, dimorder = NULL , symmetric = FALSE, fixdiag = NULL, vw = NULL, vw.convert = TRUE , dimorder.convert = TRUE, pack = TRUE, NAs = NULL, ...) ## S3 method for class 'which' as.hi(x, ...) ## S3 method for class 'double' as.hi(x, ...) ## S3 method for class 'logical' as.hi(x, maxindex = NA, dim = NULL, vw = NULL, pack = TRUE, ...) ## S3 method for class 'character' as.hi(x, names, vw = NULL, vw.convert = TRUE, ...) ## S3 method for class 'matrix' as.hi(x, dim, dimorder = NULL, symmetric = FALSE, fixdiag = NULL , vw = NULL, pack = TRUE, ...)
x |
an appropriate object of the class for which we dispatched |
envir |
the environment in which to evaluate components of the index expression |
maxindex |
maximum positive indexposition |
names |
the |
dim |
the |
dimorder |
the |
symmetric |
the |
fixdiag |
the |
vw |
the virtual window |
vw.convert |
FALSE to prevent doubly virtual window conversion, this is needed for some internal calls that have done the virtual window conversion already, see details |
dimorder.convert |
FALSE to prevent doubly dimorder conversion, this is needed for some internal calls that have done the dimorder conversion already, see details |
NAs |
a vector of NA positions to be stored |
pack |
FALSE to prevent |
range |
NULL or a vector with two elements indicating first and last position to be converted from 'bit' to 'hi' |
... |
further argument passed from generic to method or from wrapper method to |
The generic dispatches appropriately, as.hi.hi returns an hi object unchanged,
as.hi.call tries to hiparse instead of evaluate its input in order to save RAM.
If parsing is successfull as.hi.call will ignore its argument pack and always pack unless the subscript is too small to do so.
If parsing fails it evaluates the index expression and dispatches again to one of the other methods.
as.hi.name and as.hi.( are wrappers to as.hi.call.
as.hi.integer is the workhorse for coercing evaluated expressions
and as.hi.which is a wrapper removing the which class attribute.
as.hi.double, as.hi.logical and as.hi.character are also wrappers to as.hi.integer,
but note that as.hi.logical is not memory efficient because it expands all positions and then applies logical subscripting.
as.hi.matrix calls arrayIndex2vectorIndex and then as.hi.integer to interpret and preprocess matrix indices.
If the dim and dimorder parameter indicate a non-standard dimorder (dimorderStandard), the index information in x is converted from a standard dimorder interpretation to the requested dimorder.
If the vw parameter is used, the index information in x is interpreted relative to the virtual window but stored relative to the abolute origin.
Back-coercion via as.integer.hi and friends will again return the index information relative to the virtual window, thus retaining symmetry and transparency of the viurtual window to the user.
You can use length to query the index length (possibly length of negative subscripts),
poslength to query the number of selected elements (even with negative subscripts),
and maxindex to query the largest possible index position (within virtual window, if present)
Duplicated negative indices are removed and will not be recovered by as.integer.hi.
an object of class hi
Avoid changing the Hybrid Index representation, this might crash the [.ff subscripting.
Jens Oehlschlägel
hi for the Hybrid Index class, hiparse for parsing details, as.integer.hi for back-coercion, [.ff for ff subscripting
message("integer indexing with and without rel-packing")
as.hi(1:12)
as.hi(1:12, pack=FALSE)
message("if index is double, the wrapper method just converts to integer")
as.hi(as.double(1:12))
message("if index is character, the wrapper method just converts to integer")
as.hi(c("a","b","c"), names=letters)
message("negative index must use maxindex (or vw)")
as.hi(-(1:3), maxindex=12)
message("logical index can use maxindex")
as.hi(c(FALSE, FALSE, TRUE, TRUE))
as.hi(c(FALSE, FALSE, TRUE, TRUE), maxindex=12)
message("matrix index")
x <- matrix(1:12, 6)
as.hi(rbind(c(1,1), c(1,2), c(2,1)), dim=dim(x))
message("first ten positions within virtual window")
i <- as.hi(1:10, vw=c(10, 80, 10))
i
message("back-coerce relativ to virtual window")
as.integer(i)
message("back-coerce relativ to absolute origin")
as.integer(i, vw.convert=FALSE)
message("parsed index expressions save index RAM")
as.hi(quote(1:1000000000))
## Not run:
message("compare to RAM requirement when the index experssion is evaluated")
as.hi(1:1000000000)
## End(Not run)
message("example of parsable index expression")
a <- seq(100, 200, 20)
as.hi(substitute(c(1:5, 4:9, a)))
hi(c(1,4, 100),c(5,9, 200), by=c(1,1,20))
message("two examples of index expression temporarily expanded to full length due to
non-supported use of brackets '(' and mathematical operators '+' accepting token")
message("example1: accepted token but aborted parsing because length>16")
as.hi(quote(1+(1:16)))
message("example1: rejected token and aborted parsing because length>16")
as.hi(quote(1+(1:17)))Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.