r functions will not recognise apostrophe in character string - r

Question

I have a large data frame of survey data read from a .csv that looks like this when simplified.
x <- data.frame("q1" = c("yes","no","don’t_know"),
"q2" = c("no","no","don’t_know"),
"q3" = c("yes","don’t_know","don’t_know"))
I want to create a column using rowSums as below
x$dntknw<-rowSums(x=="don’t_know")
I can do it for all the yes and no answers easily, but In my dataframe it just generates zeros for the don’t_know's.
I previously had an issue with the apostrophe looking like this don’t_know. I added encoding = "UTF-8"to my read.table to fix this. However now I cant seem to get any R functions to recognise it, I tried gsub("’","",df) but this didnt work as with rowSums.
Is this a problem with the encoding? is there a regex solution to removing them? what solutions are there for dealing with this?

Answer 1

It is an encoding issue and not a regex one. I am unable to reproduce the issue and my encoding is set as UTF-8 in R. Try by setting the encoding to UTF-8 in default R rather than at the time of read.
here is my sample output with your code.
> x
q1 q2 q3 dntknw
1 yes no yes 0
2 no no don’t_know 1
3 don’t_know don’t_know don’t_know 3
> Sys.setlocale()
[1] "en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8"
Here is some more detail that may be helpful.
https://support.rstudio.com/hc/en-us/articles/200532197-Character-Encoding

Answer 2

As #Drj stated, it is probably an encoding error. When I paste your code into my console, I get
> x$q1
[1] yes no don<U+0092>t_know
Even if the encoding is off, you can still match it using regex:
grepl("don.+t_know", x$q1)
# [1] FALSE FALSE TRUE
Hence, you can calculate the row sums as follows:
x$dntknw <- rowSums(apply(x, 2, function(y) grepl("don.+t_know", y)))
Which results in
> x
q1 q2 q3 dntknw
1 yes no yes 0
2 no no don<U+0092>t_know 1
3 don<U+0092>t_know don<U+0092>t_know don<U+0092>t_know 3