sink
diverts Routput to a connection. sink.number()
reports how many diversions are in use.
sink.number(type = "message")
reports the number of the
connection currently being used for error messages.
sink(file = NULL, append = FALSE, type = c("output", "message"),
split = FALSE)sink.number(type = c("output", "message"))
NULL
to stop sink-ing.TRUE
, output will be appended to
file
; otherwise, it will overwrite the contents of
file
.TRUE
, output will be sent to the new
sink and to the current output stream, like the Unix program tee
.sink
returns NULL
. For sink.number()
the number (0, 1, 2, ...) of diversions of
output in place.
For sink.number("message")
the connection number used for
messages, 2 if no diversion has been used.
sink
for any other
purpose. The software will stop you closing one such inadvertently. Do not sink the messages stream unless you understand the source code
implementing it and hence the pitfalls.sink
diverts Routput to a connection. If file
is a
character string, a file connection with that name will be established
for the duration of the diversion. Normal Routput (to connection stdout
) is diverted by
the default type = "output"
. Only prompts and (most)
messages continue to appear on the console. Messages sent to
stderr()
(including those from message
,
warning
and stop
) can be diverted by
sink(type = "message")
(see below).
sink()
or sink(file = NULL)
ends the last diversion (of
the specified type). There is a stack of diversions for normal
output, so output reverts to the previous diversion (if there was
one). The stack is of up to 21 connections (20 diversions).
If file
is a connection it will be opened if necessary (in
"wt"
mode) and closed once it is removed from the stack of
diversions.
split = TRUE
only splits Routput (via Rvprintf
) and
the default output from writeLines
: it does not split
all output that might be sent to stdout()
.
Sink-ing the messages stream should be done only with great care.
For that stream file
must be an already open connection, and
there is no stack of connections.
If file
is a character string, the file will be opened using
the current encoding. If you want a different encoding (e.g., to
represent strings which have been stored in UTF-8), use a
file
connection --- but some ways to produce Routput
will already have converted such strings to the current encoding.
Chambers, J. M. (1998) Programming with Data. A Guide to the S Language. Springer.
capture.output
sink("sink-examp.txt")
i <- 1:10
outer(i, i, "*")
sink()
unlink("sink-examp.txt")
## capture all the output to a file.
zz <- file("all.Rout", open = "wt")
sink(zz)
sink(zz, type = "message")
try(log("a"))
## back to the console
sink(type = "message")
sink()
file.show("all.Rout")
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