matter_str-class {matter} | R Documentation |
The matter_str
class implements on-disk strings.
## Instance creation matter_str(data, datamode = "uchar", paths = NULL, filemode = ifelse(all(file.exists(paths)), "rb", "rb+"), offset = c(0, cumsum(sizeof("uchar") * extent)[-length(extent)]), extent = nchar, nchar = 0, names = NULL, encoding = "unknown", ...) ## Additional methods documented below
data |
An optional character vector which will be initially written to the data on disk if provided. |
datamode |
Must be "uchar" (or "raw") for strings. |
paths |
A 'character' vector of the paths to the files where the data are stored. If 'NULL', then a temporary file is created using |
filemode |
The read/write mode of the files where the data are stored. This should be 'rb' for read-only access, or 'rb+' for read/write access. |
offset |
A vector giving the offsets in number of bytes from the beginning of each file in 'paths', specifying the start of the data to be accessed for each file. |
extent |
A vector giving the length of the data for each file in 'paths', specifying the number of elements of size 'datamode' to be accessed from each file. |
nchar |
A vector giving the length of each element of the character vector. |
names |
The names of the data elements. |
encoding |
The character encoding to use (if known). |
... |
Additional arguments to be passed to constructor. |
An object of class matter_str
.
data
:This slot stores the information about locations of the data on disk and within the files.
datamode
:The storage mode of the accessed data when read into R. This is a 'character' vector of length one with value 'integer' or 'numeric'.
paths
:A 'character' vector of the paths to the files where the data are stored.
filemode
:The read/write mode of the files where the data are stored. This should be 'rb' for read-only access, or 'rb+' for read/write access.
chunksize
:The maximum number of elements which should be loaded into memory at once. Used by methods implementing summary statistics and linear algebra. Ignored when explicitly subsetting the dataset.
length
:The length of the data.
dim
:Either 'NULL' for vectors, or an integer vector of length one of more giving the maximal indices in each dimension for matrices and arrays.
names
:The names of the data elements for vectors.
dimnames
:Either 'NULL' or the names for the dimensions. If not 'NULL', then this should be a list of character vectors of the length given by 'dim' for each dimension. This is always 'NULL' for vectors.
ops
:Delayed operations to be applied on atoms.
encoding
:The character encoding of the strings.
matter_str
instances can be created through matter_str()
or matter()
.
Standard generic methods:
x[[i]], x[[i]] <- value
:Get or set the string elements of the vector.
x[i, j], x[i, j] <- value
:Get or set j
characters the i
th string element of the vector.
lengths(x)
:Get the number of characters (in bytes) of all string elements in the vector.
Kylie A. Bemis
x <- matter_str(c("hello", "world!")) x[]