问题
I am struggling for quite some time with outputting a raw type to standard output. Here is what I tried and did not work the desired way:
r <- as.raw(c(0x41, 0x00, 0x43)) # r = "A\0C"
cat(rawToChar(r)) # displays warning and skips data after NULL (outputs "A")
cat(r) # outputs "41 00 43"
writeBin(r, stdout()) # error: can only write to binary connection
I am looking for a way to get all three bytes / characters printed to stdout.
回答1:
If you are using an operating system that has a 'cat' or similar program, we can pipe arbitrary data to stdout like so:
con <- pipe("cat", "wb")
writeBin(as.raw(c(0x41, 0x00, 0x43)), con)
flush(con)
This has been an issue for some time, especially because we would like to use R for common gateway interface (CGI). I don't believe there is a more direct route, but you might look at the RApache source code, to see how the sendBin
function is implemented.
来源:https://stackoverflow.com/questions/7422575/how-to-write-raw-type-bytes-to-stdout