Find nonsense words in a text

Question

I have a dataset with answers of user if they know a brand or not. Some of the users just answered nonsense, as you can see in my example.

meinstring <- c("----asdada", "no idea", "C&A", "aaaaaaaaaa", "---", "adaosdjasodajsdoad")


spamidenfifier <- function(x) {
  verhaeltnis <- str_count(tolower(x), "[aeoiu]") / str_count(x)
  sequenz <- sum(sequence(rle(as.character(data.frame(strsplit(as.character(x), ""))[,1]))$lengths) >= 3, na.rm = TRUE)
  if(str_count(x) > 4) { weight <- 0.9 }  else {  weight <- 1  } ## Gewicht, weil unwahrscheinlicher bei längerem String
  variation_buchstaben <- (length(unique(data.frame(strsplit(as.character(x), ""))[,1])) / str_count(x) * weight)
  if(verhaeltnis < 0.2 | verhaeltnis > 0.8 | sequenz > 0 | variation_buchstaben < 0.5) {
    return(TRUE)
  } else {
    return(FALSE)
  }
}


sapply(meinstring, spamidenfifier)

Output:

----asdada            no idea                C&A         aaaaaaaaaa                --- adaosdjasodajsdoad 
      TRUE              FALSE              FALSE               TRUE               TRUE              FALSE 

My function does not work too bad, however there might be better solutions. Is there a package or better method to identify if a word was just misspelled or a person answered nonsense. If not, suggestions to improve that function are highly appreciated!

edit: Updated some improvements :-)

Answer 1

Just my spontaneous idea:

meinstring <- c("----asdada", "no idea", "C&A", "aaaaaaaaaa", "---", "adaosdjasodajsdoad", "+-*-", "*-+-", "adfpdflrraaeea")

grepl('^\\W+$|(?:[-!@#$%^&*\\[\\]()";:_<>.,=+/ ]){2,}|[-!@#$%^&*\\[\\]()";:_<>.,=+/ ]{3,}|[aeoiu]{3,}',
meinstring , perl = T) & !grepl("iou|zweieiig", meinstring) # add the exceptions in the second grepl.

[1]  TRUE FALSE FALSE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE

---

There is no neat perfect solution.