R script to add variables to FanGraphs leaderboard data

fg_data_prep.R

# preparation work for FanGraphs leaderboard data

# collected FanGraphs Leaderboard batting data
# choose Multiple Seasons (all), Split Seasons
# minimum 100 PA in each season
# download data and saved as "fgbatting.csv"

library(dplyr)
library(readr)
library(Lahman)
library(purrr)

# read data and do some data maintenance

fg <- read_csv("fgbatting.csv")
names(fg)[c(10, 11, 19)] <-
     c("BB_Pct", "K_Pct", "wRC_plus")
fg$BB_Pct <- as.numeric(gsub("[\\%,]", "", fg$BB_Pct))
fg$K_Pct <- as.numeric(gsub("[\\%,]", "", fg$K_Pct))

# merge Lahman ids from chadwick database
# see https://github.com/chadwickbureau/register

people <- read_csv("people.csv")
inner_join(fg,
      select(people, key_bbref, key_fangraphs),
      by = c("playerid" = "key_fangraphs")) -> fg

# add career PA, midyear, and ages to data file

Batting %>%
  mutate(PA = ifelse(is.na(SF) == FALSE,
                     AB + BB + SH + SF + HBP,
                     AB + BB + SH + HBP)) %>%
  group_by(playerID) %>%
  summarize(minYear = min(yearID),
            maxYear = max(yearID),
            midYear = (minYear + maxYear) / 2,
            cPA = sum(PA),
            .groups = "drop") %>%
  select(playerID, midYear, cPA) -> S

# collect birthyears

get_birthyear <- function(playerid) {
  Master %>%
    filter(playerID == playerid)  %>%
    mutate(birthyear = ifelse(birthMonth >= 7,
                              birthYear + 1, birthYear)) %>%
    select(playerID, birthyear)
}

player_ids <- unique(fg$key_bbref)
S1 <- map_df(player_ids, get_birthyear)

# merge birthyears with summary dataset

inner_join(S, S1, by = "playerID") -> S2

# merge the fangraphs and summary datasets

inner_join(fg, S2,
           by = c("key_bbref" = "playerID")) -> fg

# compute ages

fg %>%
  mutate(Age = Season - birthyear) -> fg

# read in baseball reference HOF list
# downloaded from
# https://www.baseball-reference.com/awards/hof.shtml

hof <- read_csv("bref_hof.csv")
extract_name <- function(name){
  unlist(strsplit(name, "\\\\"))[2]
}
hof$playerID <- sapply(hof$Name, extract_name)
hof$inducted <- "Y"

# merge with original dataset
left_join(fg, select(hof,
                 playerID, inducted),
          by = c("key_bbref" = "playerID")) -> fg

# write csv and tab-deliminted versions of data
write_csv(fg, "fgbatting_complete.csv")

write_delim(fg, "fg_batting_leaderboard.txt")

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