Split a string and keep delimiter

Question

Lets say I have a string:

StringA/StringB/StringC

Is there any way I can split this string by the / symbol, but keep it in the returned values:

StringA
/StringB
/StringC

Maël · Answer 1 · 2022-11-02T16:29:43.097

6

Yes, with a look-ahead: (?=/)

library(stringr)
str_split(str, "(?=/)")

#[[1]]
#[1] "StringA"  "/StringB" "/StringC"

Works equally well with tidyr separating function:

tidyr::separate_rows(data.frame(str), str, sep = "(?=/)")

#  str        
#1 StringA 
#2 /StringB
#3 /StringC

With base R's strsplit, look-aheads are less straightforwards, but this works well:

unlist(strsplit(str, "(?<=.)(?=[/])", perl = TRUE))
#[1] "StringA"  "/StringB" "/StringC"

And reversely:

unlist(strsplit(str, "(?<=/)", perl = TRUE))
#[1] "StringA/" "StringB/" "StringC"

edited Nov 02 '22 at 16:29

answered Nov 02 '22 at 16:02

Maël

Thanks! Likewise, how would it work if I wanted it to end with the / instead? – jackahall Nov 02 '22 at 16:10
1

With a look-behind: `str_split(str, "(?<=/)")`. – Maël Nov 02 '22 at 16:10

score 4 · Answer 2 · answered Nov 02 '22 at 16:05

4

You can try scan + gsub like below

> scan(text = gsub("/", " /", "StringA/StringB/StringC"), what = "")
Read 3 items
[1] "StringA"  "/StringB" "/StringC"

answered Nov 02 '22 at 16:05

ThomasIsCoding

score 1 · Answer 3 · answered Nov 02 '22 at 16:45

1

With str_extract

library(stringr)
str_extract_all(str1, "/?[^/]+")[[1]]
[1] "StringA"  "/StringB" "/StringC"

answered Nov 02 '22 at 16:45

akrun

3 Answers3