How can I split a string "a\n\nb" into c("a", "", "", "b")?

Question

When I stringr::str_split "\n\na\n" by "\n", I obtain c("", "", "a", "").

I expected I can obtain c("a", "", "", "b") when I stringr::str_split "a\n\nb" by "\n", but I obtained c("a", "", "b") instead. How can I obtain c("a", "", "", "b") by splitting "a\n\n\a"?

Try:

stringr::str_split("a\n\nb", "\n")

Expect:

c("a", "", "", "b")

Result:

c("a", "", "b")

Answer 1

Assuming that we want to extract each character separately, just split on the blank and remove all the \n to return blanks for the split elements

str_remove_all(strsplit(str1, "")[[1]], "\n")
[1] "a" ""  ""  "b"

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Or use perl = TRUE with \n?

strsplit(str1, "\n?", perl = TRUE)[[1]]
[1] "a" ""  ""  "b"

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If it should be at each \n only

strsplit(str_replace(str1, "(\n\\S)", "\n\\1"), "\n")[[1]]
[1] "a" ""  ""  "b"

data

str1 <- "a\n\nb"

Answer 2

You are getting the correct result, even if it's not what you expect. The length of the result equals the number of delimiters in the string + 1. Thus if you want an extra field, you need to add an extra delimiter:

x1 <- "a\n\nb"
x2 <- "abc\n\ndef"

strsplit(gsub("(\n{2,})", "\\1\n", x1), "\n")[[1]]
[1] "a" ""  ""  "b"

strsplit(gsub("(\n{2,})", "\\1\n", x2), "\n")[[1]]
[1] "abc" ""    ""    "def"