Raw Vectors

Description

Creates or tests for objects of type "raw".

Usage

raw(length = 0)
as.raw(x)

Arguments

Details

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).

Value

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.

See Also

charToRaw, rawShift, etc.

Examples

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)

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)