CODEWITHSUNDEEP
r
Mahesh Yadav
Mahesh Yadav

Reputation: 101

End of line character missing with capture.output in R

In R, when I print/cat in a function, it is printed properly in stdout when the function is called. When I put the output in a variable via capture.output, the end-of-line character "\n" is missing.

Here is simple R code example:

ff <- function(){ print(-5:-1);cat("dummy line\n");print(1:5)}
ff()

gives the output:

[1] -5 -4 -3 -2 -1
dummy line
[1] 1 2 3 4 5

and the following code gives output in single line.

ff_out<-capture.output(ff())
ff_out

gives the same output in one line (i.e., with "\n" missing)

I must be missing something very simple. Please help me resolve this to get the same output as shown above.

Upvotes: 2

Views: 484

Answers (1)

Frank
Frank

Reputation: 66819

It's not actually "in one line". It's a vector of length three, where each element is one of the lines. You can

cat(ff_out, sep="\n")

# [1] -5 -4 -3 -2 -1
# dummy line
# [1] 1 2 3 4 5

To inspect an object, str is useful, like 

str(ff_out)
#  chr [1:3] "[1] -5 -4 -3 -2 -1" "dummy line" "[1] 1 2 3 4 5"

The part at the start indicates that it is a character vector of length three.

Upvotes: 1

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