raw {base} | R Documentation |
Creates or tests for objects of type "raw"
.
raw(length = 0)
as.raw(x)
is.raw(x)
length |
desired length. |
x |
object to be coerced. |
The raw type is intended to hold raw bytes. It is possible to extract subsequences of bytes, and to replace elements (but only by elements of a raw vector). The relational operators (see Comparison) work, as do the logical operators (see Logic) with a bitwise interpretation.
A raw vector is printed with each byte separately represented as a
pair of hex digits. If you want to see a character representation
(with escape sequences for non-printing characters) use
rawToChar
.
Coercion to raw treats the input values as representing a small
(decimal) integers, so the input is first coerced to integer, and then
values which are outside the range [0 ... 255]
or are
NA
are set to 0
(the nul
byte).
raw
creates a raw vector of the specified length.
Each element of the vector is equal to 0
.
Raw vectors are used to store fixed-length sequences of bytes.
as.raw
attempts to coerce its argument to be of raw
type. The (elementwise) answer will be 0
unless the
coercion succeeds (or if the original value successfully coerces to 0).
is.raw
returns true if and only if typeof(x) == "raw"
.
charToRaw
, rawShift
, etc.
xx <- raw(2)
xx[1] <- as.raw(40) # NB, not just 40.
xx[2] <- charToRaw("A")
xx
x <- "A test string"
(y <- charToRaw(x))
is.vector(y) # TRUE
rawToChar(y)
is.raw(x)
is.raw(y)
isASCII <- function(txt) all(charToRaw(txt) <= as.raw(127))
isASCII(x) # true
isASCII("\x9c25.63") # false (in Latin-1, this is an amount in UK pounds)