Removing only empty parenthesis in R

Question

I am working with some headers and I need to remove parenthesis in the headers but only where is nothing inside but to keep the others if it has the unit of measure. e.g.

"Sample_No ()"  - Sample_No
"SOC (%)" - "SOC (%)"

Example

I've edited this but for operations involving only textual input and output it may be better to provide simple text. It will the question more accessible, especially for people using screen readers, etc. — Konrad, Dec 18 '21 at 18:33

akrun · Accepted Answer · 2021-12-18T18:29:40.830

If it is empty parentheses match the open parentheses followed by the closing parentheses without any other characters and replace with blank ("") in gsub (if there is a chance of more than one matches) or with the example even sub is enough)

gsub("\\s*\\(\\)", "", v1)

-output

[1] "Sample_No" "SOC (%)"

Or use str_remove from stringr

library(stringr)
trimws(str_remove_all(v1, fixed("()")))
[1] "Sample_No" "SOC (%)"

data

v1 <- c("Sample_No ()", "SOC (%)")

score 1 · Answer 2 · answered Dec 18 '21 at 18:24

Using gsub with a regular expression. \\s denotes whitespace \\( and \\) the parentheses that have to be escaped.

x <- c("Sample_No ()", "Sample_No", "SOC (%)", "SOC (%)")

gsub('\\s\\(\\)', '', x)
# [1] "Sample_No" "Sample_No" "SOC (%)"   "SOC (%)"

score 1 · Answer 3 · answered Dec 18 '21 at 18:24

1

Using gsub you could do:

header <- c("Sample_No ()", "SOC (%)")

gsub("\\s*\\(\\)", "", header)
#> [1] "Sample_No" "SOC (%)"

answered Dec 18 '21 at 18:24

stefan

90,330
6
25
51

@TomasV You are welcome. But in my opinion akrun deserves the credit for the accepted answer. Not only was he the first to answer but also is his answer more complete than mine. – stefan Dec 18 '21 at 18:45

score 0 · Answer 4 · answered Dec 18 '21 at 18:28

For completeness, you may wan to explore the stringi package. The code below also trims potential empty spaces that may be left after the operation.

vecA <- c("Sample_No ()", "SOC (%)")
stringi::stri_trim_both(
    stringi::stri_replace_all(str = vecA, replacement = "",  fixed = "()")
)
# [1] "Sample_No" "SOC (%)"

This particular operation is trivial, but stringi comes in handy for more complex operations.

Removing only empty parenthesis in R

Example

4 Answers4

data