I need to process some data that are mostly csv. The problem is that R ignores the comma if it comes at the end of a line (e.g., the one that comes after 3 in the example below).
> strsplit("1,2,3,", ",")
[[1]]
[1] "1" "2" "3"
I'd like it to be read in as [1] "1" "2" "3" NA
instead. How can I do this? Thanks.
Here are a couple ideas
scan(text="1,2,3,", sep=",", quiet=TRUE)
#[1] 1 2 3 NA
unlist(read.csv(text="1,2,3,", header=FALSE), use.names=FALSE)
#[1] 1 2 3 NA
Those both return integer vectors. You can wrap as.character
around either of them to get the exact output you show in the Question:
as.character(scan(text="1,2,3,", sep=",", quiet=TRUE))
#[1] "1" "2" "3" NA
Or, you could specify what="character"
in scan
, or colClasses="character"
in read.csv
for slightly different output
scan(text="1,2,3,", sep=",", quiet=TRUE, what="character")
#[1] "1" "2" "3" ""
unlist(read.csv(text="1,2,3,", header=FALSE, colClasses="character"), use.names=FALSE)
#[1] "1" "2" "3" ""
You could also specify na.strings=""
along with colClasses="character"
unlist(read.csv(text="1,2,3,", header=FALSE, colClasses="character", na.strings=""),
use.names=FALSE)
#[1] "1" "2" "3" NA