I am trying to remove a block of text that wraps around what I want to keep. So I wanted to assign variables since the text can be long. This is an example of what I am trying to do. [Doesn't remove the text]
Text<-'This is an example text [] test'
topheader<-'This'
bottomheader<-'test'
gsubfn(".", list(topheader = "", bottomheader = ""), Text)
[1] "This is an example text [] test"
Goal: "is an example text []"
I think this is one solution to what you're looking for:
# Your data:
Text<-'This is an example text [] test'
topheader<-'This'
bottomheader<-'test'
# A possible solution fn
gsubfn <- function(text, th, bh, th.replace="", bh.replace="") {
answer <- gsub(text,
pattern=paste0(th," (.*) ",bh),
replacement=paste0(th.replace,"\\1",bh.replace)
)
return(answer)
}
# Your req'd answer
gsubfn(text=Text,th=topheader,bh=bottomheader)
# Another example
gsubfn(text=Text,th=topheader,bh=bottomheader,th.replace="@@@ ",bh.replace=" ###")
You can just collapse your search words into a regex string.
Test <- 'This is an example text testing [] test'
top <- "This"
bottom <- "test"
arg <- c(top, bottom)
arg <- paste(arg, collapse="|")
arg <- gsub("(\\w+)", "\\\\b\\1\\\\b", arg)
Test.c <- gsub(arg, "", Test)
Test.c <- gsub("[ ]+", " ", Test.c)
Test.c <- gsub("^[[:space:]]|[[:space:]]$", "", Test.c)
Test.c
# "is an example text []"
Or using magrittr
pipes
library(magrittr)
c(top, bottom) %>%
paste(collapse="|") %>%
gsub("(\\w+)", "\\\\b\\1\\\\b", .) %>%
gsub(., "", Test) %>%
gsub("[ ]+", " ", .) %>%
gsub("^[[:space:]]|[[:space:]]$", "", .) -> Test.c
Test.c
# "is an example text []"
Or using a loop
Test.c <- Test
words <- c(top, bottom)
for (i in words) {
Test.c <- gsub(paste0("\\\\b", i, "\\\\b"), "", Test)
}
Test.c <- gsub("[ ]+", " ", Test.c)
Test.c <- gsub("^[[:space:]]|[[:space:]]$", "", Test.c)
Test.c
# "is an example text []"
1) gsubfn There are several problems here:
the regular expression in gsubfn
(and in gsub
) must match the string you want to process but a dot matches only a single character so it can never match This
or test
which are 4 character strings. Use "\\\\w+"
instead.
In list(a = x)
the a
must be a constant, not a variable. Write out the names explicitly or use setNames
instead if they are in variables.
Thus to fix up the code in the question:
library(gsubfn)
trimws(gsubfn("\\w+", list(This = "", text = ""), Text))
## [1] "is an example [] test"
or in terms of the header variables:
L <- setNames(list("", ""), c(topheader, bottomheader))
trimws(gsubfn("\\w+", L, Text))
## [1] "is an example [] test"
Note that this will replace any occurrence of topheader and bottomheader and not just ones at the start and end; however, this seems to be the closest to your code that is likely sufficient.
2) sub Another possibility is this simple sub
sub("^This (.*) text$", "\\1", Text)
[1] "is an example [] test"
or in terms of the header variables:
pat <- sprintf("^%s (.*) %s$", topheader, bottomheader)
sub(pat, "\\1", Text)
## [1] "is an example [] test"
Update: Fixed (1)
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.