R/getWAR.R

In frogman141/openWAR: Machinery for analyzing baseball data and computing WAR

#' @title getWAR
#' @aliases getWAR.openWARPlays
#'
#' @description Tabulates WAR
#' 
#' @details Compute each player's WAR, given their RAA values
#' 
#' @param data An object of class \code{'openWARPlays'}
#' @param dataRepl An object of class \code{'openWARPlays'} that will be used to calculate the replacement level.  
#' @param nteams The nteams argument to be passed to getReplacementPlayers
#' 
#' @export getWAR
#' @export getWAR.openWARPlays
#' 
#' @examples
#' 
#' ds = getData()
#' out = makeWAR(ds)
#' raa = getRAA(out$openWAR)
#' war = getWAR(raa)

getWAR = function(data, dataRepl = NULL, nteams = 30, verbose = TRUE, ...) UseMethod("getWAR")

getWAR.openWARPlays = function(data, dataRepl = NULL, nteams = 30, verbose = TRUE, ...) {
    # If no dataRepl is provided, then use all the data to define replacement level.
    if (is.null(dataRepl)) {
        dataRepl <- data
    }
    # Compute RAA for all players
    players = getRAA(data)
    
    # Get the replacement level players
    playersRepl = getRAA(dataRepl)
    replIds = getReplacementPlayers(playersRepl, nteams)
    repl = playersRepl[playersRepl$playerId %in% replIds, ]
    
    if (verbose) {
        message(paste("...identified", nrow(repl), "replacement-level players..."))
    }
    
    # Find the playing time matrix for all players
    pt.mat = as.matrix(players[, c("PA.bat", "PA.br1", "PA.br2", "PA.br3", "BF", "PA.P", "PA.C",
                                   "PA.1B", "PA.2B", "PA.3B", "PA.SS", "PA.LF", "PA.CF", "PA.RF")])
    
    repl.means = getReplacementMeans(dataRepl, replIds)
    players$repl = as.numeric(pt.mat %*% repl.means)
    
    # Attach the replacement values to the list of players war = merge(x=players, y=data.frame(batterId = row.names(repl.value),
    # repl = repl.value), all.x = TRUE)
    war <- mutate(players, WAR = (RAA - repl)/10)
    war <- mutate(war, isReplacement = playerId %in% replIds)
    class(war) = c("openWARPlayers", class(war))
    return(war)
}