I have the following simple R code:
sink("output.txt", type=c("output", "message")) cat("Hello", append = TRUE) cat("World", append = TRUE) sink(NULL) It just writes the R console into a text file. I want to put it in an R source file (".r") and run it multiple times. I want to have the output as follows:
file.show("output.txt") Hello World Hello World If I run it two times, I now see:
Hello World It looks like it has been overwritten.
sink() has its own append argument. And as Gregor mentioned, append in cat() only works when file is used.
However, you don't need to use append at all if you put all the cat() calls between the sink() calls, as sink() will continue to append to the file until you call sink(NULL)
But for your case, I think you want to do something like this for your sink() chunk:
sink("output.txt", type=c("output", "message"), append = TRUE) cat("Hello", "\n") cat("World", "\n") sink(NULL) Or more simply,
sink("output.txt", type=c("output", "message"), append = TRUE) cat("Hello", "World", sep = "\n") sink(NULL) Repeating this operation twice, we have created the file and appended to it
Hello World Hello World 
sink("output.txt", type=c("output", "message"), append=TRUE)?cat, theappendargument only matters if you're using thefileargument ofcat.