readBin {base} | R Documentation |
Read binary data from a connection, or write binary data to a connection.
readBin(con, what, n = 1, size = NA, endian = .Platform$endian) writeBin(object, con, size = NA, endian = .Platform$endian)
con |
A connection object or a character string. |
what |
Either an object whose mode will give the mode of the
vector to be read, or a character vector of length one describing
the mode: one of "numeric", "double", "integer", "int",
"logical", "complex", "character" . |
n |
integer. The (maximal) number of records to be
read. You can use an over-estimate here, but not too large as
storage is reserved for n items. |
size |
integer. The number of bytes per element in the byte
stream. The default, NA , uses the natural size. Size changing
is not supported for complex vectors. |
endian |
The endian-ness ("big" or "little" of the
target system for the file. Using "swap" will force swapping
endian-ness. |
object |
An R object to be written to the connection. |
If the con
is a character string, the functions call
file
to obtain an file connection which is opened for
the duration of the function call.
If the connection is open it is read/written from its current position. If it is not open, it is opened for the duration of the call and then closed again.
If size
is specified and not the natural size of the object,
each element of the vector is coerced to an appropriate type before
being written or as it is read. Possible sizes are 1, 2, 4 and
possibly 8 for integer or logical vectors, and 4, 8 and possibly 12/16
for numeric vectors. (Note that coercion occurs as signed types.)
Changing sizes is unlikely to preserve NA
s, and the extended
precision sizes are unlikely to be portable across platforms.
For readBin
, a vector of appropriate mode and the number of
items read (which might be less than n
).
For writeBin
, none.
Integer read/writes of size 8 will be available if either C type
long
is of size 8 bytes or C type long long
exists and
is of size 8 bytes.
Real read/writes of size sizeof(long double)
(usually 12 or 16
bytes) will be available only if that type is available and different
from double
.
connection
, readLines
, writeLines
zz <- file("testbin", "wb") writeBin(1:10, zz) writeBin(pi, zz, endian="swap") writeBin(pi, zz, size=4) writeBin(pi^2, zz, size=4, endian="swap") writeBin(pi+3i, zz) writeBin("A test of a connection", zz) z <- paste("A very long string", 1:100, collapse=" + ") writeBin(z, zz) close(zz) zz <- file("testbin", "rb") readBin(zz, integer(), 4) readBin(zz, integer(), 6) readBin(zz, numeric(), 1, endian="swap") readBin(zz, numeric(), size=4) readBin(zz, numeric(), size=4, endian="swap") readBin(zz, complex(), 1) readBin(zz, character(), 1) z2 <- readBin(zz, character(), 1) close(zz) unlink("testbin") stopifnot(z2 == z)