Given a known Wordle answer, backwards-engineer someone's prior guess

eldrow.R

# I tweeted about this:
#     https://twitter.com/mattdray/status/1481561924202553346
# Then I blogged about it:
#     https://www.rostrum.blog/2022/01/14/wordle/

# remotes::install_github("coolbutuseless/wordle")

eldrow <- function(guess, answer, words = wordle::wordle_dict){
  
  answer <- tolower(answer)
  guess <- toupper(guess)
  
  guess_chars <- strsplit(guess, "")[[1]]
  answer_chars <- strsplit(answer, "")[[1]]
  
  exact <- ifelse(guess_chars == "G", answer_chars, ".") |>
    paste0(collapse = "")
  
  wrong_spot <- gsub(
    "\\.", "", ifelse(guess_chars == "Y", answer_chars, ".")
  )
  
  exact_chars <- regmatches(exact, gregexpr("\\w", exact))[[1]]
  correct_chars_table <- table(
    c(exact_chars, wrong_spot[wrong_spot != ""])
  )
  min_count <- as.vector(correct_chars_table)
  names(min_count) <- names(correct_chars_table)
  
  possibles <- wordle::filter_words(
    words, exact, wrong_spot, min_count, min_count
  )
  
  possibles <- possibles[which(possibles != answer)]
  possibles[order(possibles)]
  
}

guess_2 <- eldrow(guess = "-GGG-", answer = "shirt")

lapply(guess_2, \(x) eldrow("YGG--", x)) |> 
  lapply(\(x) x[which(x != "shirt")]) |>
  setNames(guess_2)