AMR/R/mic.R

# ==================================================================== #
# TITLE                                                                #
# Antimicrobial Resistance (AMR) Analysis                              #
#                                                                      #
# SOURCE                                                               #
# https://github.com/msberends/AMR                                     #
#                                                                      #
# LICENCE                                                              #
# (c) 2018-2020 Berends MS, Luz CF et al.                              #
#                                                                      #
# This R package is free software; you can freely use and distribute   #
# it for both personal and commercial purposes under the terms of the  #
# GNU General Public License version 2.0 (GNU GPL-2), as published by  #
# the Free Software Foundation.                                        #
#                                                                      #
# We created this package for both routine data analysis and academic  #
# research and it was publicly released in the hope that it will be    #
# useful, but it comes WITHOUT ANY WARRANTY OR LIABILITY.              #
# Visit our website for more info: https://msberends.github.io/AMR.    #
# ==================================================================== #

#' Class 'mic'
#'
#' This transforms a vector to a new class [`mic`], which is an ordered [`factor`] with valid MIC values as levels. Invalid MIC values will be translated as `NA` with a warning.
#' @inheritSection lifecycle Stable lifecycle
#' @rdname as.mic
#' @param x vector
#' @param na.rm a logical indicating whether missing values should be removed
#' @details To interpret MIC values as RSI values, use [as.rsi()] on MIC values. It supports guidelines from EUCAST and CLSI.
#' @return Ordered [`factor`] with new class [`mic`]
#' @aliases mic
#' @export
#' @seealso [as.rsi()]
#' @inheritSection AMR Read more on our website!
#' @examples
#' mic_data <- as.mic(c(">=32", "1.0", "1", "1.00", 8, "<=0.128", "8", "16", "16"))
#' is.mic(mic_data)
#'
#' # this can also coerce combined MIC/RSI values:
#' as.mic("<=0.002; S") # will return <=0.002
#'
#' # interpret MIC values
#' as.rsi(x = as.mic(2),
#'        mo = as.mo("S. pneumoniae"),
#'        ab = "AMX",
#'        guideline = "EUCAST")
#' as.rsi(x = as.mic(4),
#'        mo = as.mo("S. pneumoniae"),
#'        ab = "AMX",
#'        guideline = "EUCAST")
#'
#' plot(mic_data)
#' barplot(mic_data)
as.mic <- function(x, na.rm = FALSE) {
  if (is.mic(x)) {
    x
  } else {
    x <- x %>% unlist()
    if (na.rm == TRUE) {
      x <- x[!is.na(x)]
    }
    x.bak <- x
    
    # comma to period
    x <- gsub(",", ".", x, fixed = TRUE)
    # transform Unicode for >= and <=
    x <- gsub("\u2264", "<=", x, fixed = TRUE)
    x <- gsub("\u2265", ">=", x, fixed = TRUE)
    # remove space between operator and number ("<= 0.002" -> "<=0.002")
    x <- gsub("(<|=|>) +", "\\1", x)
    # transform => to >= and =< to <=
    x <- gsub("=<", "<=", x, fixed = TRUE)
    x <- gsub("=>", ">=", x, fixed = TRUE)
    # starting dots must start with 0
    x <- gsub("^[.]+", "0.", x)
    # values like "<=0.2560.512" should be 0.512
    x <- gsub(".*[.].*[.]", "0.", x)
    # remove ending .0
    x <- gsub("[.]+0$", "", x)
    # remove all after last digit
    x <- gsub("[^0-9]+$", "", x)
    # keep only one zero before dot
    x <- gsub("0+[.]", "0.", x)
    # starting 00 is probably 0.0 if there's no dot yet
    x[!x %like% "[.]"] <- gsub("^00", "0.0", x[!x %like% "[.]"])
    # remove last zeroes
    x <- gsub("([.].?)0+$", "\\1", x)
    x <- gsub("(.*[.])0+$", "\\10", x)
    # remove ending .0 again
    x[x %like% "[.]"] <- gsub("0+$", "", x[x %like% "[.]"])
    # never end with dot
    x <- gsub("[.]$", "", x)
    # force to be character
    x <- as.character(x)
    # trim it
    x <- trimws(x)
    
    ## previously unempty values now empty - should return a warning later on
    x[x.bak != "" & x == ""] <- "invalid"
    
    # these are allowed MIC values and will become factor levels
    ops <- c("<", "<=", "", ">=", ">")
    lvls <- c(c(t(sapply(ops, function(x) paste0(x, "0.00", 1:9)))),
              unique(c(t(sapply(ops, function(x) paste0(x, sort(as.double(paste0("0.0", 
                                                                                 sort(c(1:99, 125, 128, 256, 512, 625)))))))))),
              unique(c(t(sapply(ops, function(x) paste0(x, sort(as.double(paste0("0.", 
                                                                                 c(1:99, 125, 128, 256, 512))))))))),
              c(t(sapply(ops, function(x) paste0(x, sort(c(1:9, 1.5)))))),
              c(t(sapply(ops, function(x) paste0(x, c(10:98)[9:98 %% 2 == TRUE])))),
              c(t(sapply(ops, function(x) paste0(x, sort(c(2 ^ c(7:10), 80 * c(2:12))))))))
    
    na_before <- x[is.na(x) | x == ""] %>% length()
    x[!x %in% lvls] <- NA
    na_after <- x[is.na(x) | x == ""] %>% length()
    
    if (na_before != na_after) {
      list_missing <- x.bak[is.na(x) & !is.na(x.bak) & x.bak != ""] %>%
        unique() %>%
        sort()
      list_missing <- paste0('"', list_missing, '"', collapse = ", ")
      warning(na_after - na_before, " results truncated (",
              round(((na_after - na_before) / length(x)) * 100),
              "%) that were invalid MICs: ",
              list_missing, call. = FALSE)
    }
    
    structure(.Data = factor(x, levels = lvls, ordered = TRUE),
              class =  c("mic", "ordered", "factor"))
  }
}

all_valid_mics <- function(x) {
  x_mic <- tryCatch(suppressWarnings(as.mic(x[!is.na(x)])),
                    error = function(e) NA)
  !any(is.na(x_mic)) & !all(is.na(x))
}

#' @rdname as.mic
#' @export
is.mic <- function(x) {
  inherits(x, "mic")
}

#' @method as.double mic
#' @export
#' @noRd
as.double.mic <- function(x, ...) {
  as.double(gsub("(<|=|>)+", "", as.character(x)))
}

#' @method as.integer mic
#' @export
#' @noRd
as.integer.mic <- function(x, ...) {
  as.integer(gsub("(<|=|>)+", "", as.character(x)))
}

#' @method as.numeric mic
#' @export
#' @noRd
as.numeric.mic <- function(x, ...) {
  as.numeric(gsub("(<|=|>)+", "", as.character(x)))
}

#' @method droplevels mic
#' @export
#' @noRd
droplevels.mic <- function(x, exclude = ifelse(anyNA(levels(x)), NULL, NA), ...) {
  x <- droplevels.factor(x, exclude = exclude, ...)
  class(x) <- c("mic", "ordered", "factor")
  x
}

#' @method print mic
#' @export
#' @noRd
print.mic <- function(x, ...) {
  cat("Class <mic>\n")
  print(as.character(x), quote = FALSE)
}

#' @method summary mic
#' @export
#' @noRd
summary.mic <- function(object, ...) {
  x <- object
  n_total <- x %>% length()
  x <- x[!is.na(x)]
  n <- x %>% length()
  c(
    "Class" = "mic",
    "<NA>" = n_total - n,
    "Min." = sort(x)[1] %>% as.character(),
    "Max." = sort(x)[n] %>% as.character()
  )
}

#' @method plot mic
#' @export
#' @importFrom graphics barplot axis par
#' @noRd
plot.mic <- function(x,
                     main = paste("MIC values of", deparse(substitute(x))),
                     ylab = "Frequency",
                     xlab = "MIC value",
                     axes = FALSE,
                     ...) {
  barplot(table(droplevels.factor(x)),
          ylab = ylab,
          xlab = xlab,
          axes = axes,
          main = main,
          ...)
  axis(2, seq(0, max(table(droplevels.factor(x)))))
}

#' @method barplot mic
#' @export
#' @importFrom graphics barplot axis
#' @noRd
barplot.mic <- function(height,
                        main = paste("MIC values of", deparse(substitute(height))),
                        ylab = "Frequency",
                        xlab = "MIC value",
                        axes = FALSE,
                        ...) {
  barplot(table(droplevels.factor(height)),
          ylab = ylab,
          xlab = xlab,
          axes = axes,
          main = main,
          ...)
  axis(2, seq(0, max(table(droplevels.factor(height)))))
}

#' @method [ mic
#' @export
#' @noRd
"[.mic" <- function(x, ...) {
  y <- NextMethod()
  attributes(y) <- attributes(x)
  y
}
#' @method [[ mic
#' @export
#' @noRd
"[[.mic" <- function(x, ...) {
  y <- NextMethod()
  attributes(y) <- attributes(x)
  y
}
#' @method [<- mic
#' @export
#' @noRd
"[<-.mic" <- function(i, j, ..., value) {
  value <- as.mic(value)
  y <- NextMethod()
  attributes(y) <- attributes(i)
  y
}
#' @method [[<- mic
#' @export
#' @noRd
"[[<-.mic" <- function(i, j, ..., value) {
  value <- as.mic(value)
  y <- NextMethod()
  attributes(y) <- attributes(i)
  y
}
#' @method c mic
#' @export
#' @noRd
c.mic <- function(x, ...) {
  y <- NextMethod()
  attributes(y) <- attributes(x)
  y
}