Remove parentheses and text within from strings in R

You could also use:

library(qdap)
companies$Name <-  genX(companies$Name, " (", ")")

companies
        Name
1  Company A Inc
2       CompanyB
3 Company C Inc.
4 Company D Inc.
5       CompanyE

A gsub should work here

gsub("\\s*\\([^\\)]+\\)","",as.character(companies$Name))
# or using "raw" strings as of R 4.0
gsub(r"{\s*\([^\)]+\)}","",as.character(companies$Name))

# [1] "Company A Inc"  "Company B"      "Company C Inc."
# [4] "Company D Inc." "Company E" 

Here we just replace occurrences of "(...)" with nothing (also removing any leading space). R makes it look worse than it is with all the escaping we have to do for the parenthesis since they are special characters in regular expressions.

You could use stringr::str_replace. It's nice because it accepts factor variables.

companies <- data.frame(Name=c("Company A Inc (COMPA)","Company B (BEELINE)", 
                               "Company C Inc. (Coco)", "Company D Inc.", 
                               "Company E"))

library(stringr)
str_replace(companies$Name, " \\s*\\([^\\)]+\\)", "")
# [1] "Company A Inc"  "Company B"      "Company C Inc." 
# [4] "Company D Inc." "Company E"

And if you still want to use strsplit, you could do

companies$Name <- as.character(companies$Name)
unlist(strsplit(companies$Name, " \\(.*\\)"))
# [1] "Company A Inc"  "Company B"      "Company C Inc."
# [4] "Company D Inc." "Company E"