Ryan Howard Runs Value Platoon Splits Work

ryan.platoon.R

#########################################################
# Ryan Howard platoon advantage R work
#########################################################

# download Ryan.csv from https://docs.google.com/spreadsheets/d/1KRwk03LT4EaRA14oeEJlTE0rqoL88j3B11r1TB36O2U/edit?usp=sharing
# save as a csv file "Ryan.csv" in current working directory

Ryan <- read.csv("Ryan.csv")

library(dplyr)

# finds mean run value and PA for each season and pitching hand

Runs.Season.Pitcher <- summarize(group_by(Ryan, Season, PIT_HAND_CD),
               Mean=mean(RUNS.VALUE),
               PA=length(RUNS.VALUE))

# finds mean run value and PA for each season

Runs.Season <- summarize(group_by(Ryan, Season),
                Mean=mean(RUNS.VALUE),
                PA=length(RUNS.VALUE))

Runs.Season$PIT_HAND_CD <- "Overall"

# graphs the left, right, and overall mean runs value against 
# season

library(ggplot2)
print(ggplot(rbind(Runs.Season.Pitcher, Runs.Season), 
         aes(Season, Mean, color=PIT_HAND_CD)) +
         geom_point(size=2) + geom_line(size=2) +
         labs(title="Ryan Howard's Mean Run Values") +
         theme(plot.title = element_text(size = rel(2))) +
         theme(axis.text = element_text(size = rel(2))) +
         theme(axis.title = element_text(size = rel(2))) +
         theme(legend.text = element_text(size = rel(1.5))) +
         theme(legend.title = element_text(size = rel(1.5)))
         )

# merges the left and right split data horizontally

Merged.Runs <- merge(subset(Runs.Season.Pitcher, PIT_HAND_CD=="R"),
            subset(Runs.Season.Pitcher, PIT_HAND_CD=="L"),
            by="Season")

plot(ggplot(Merged.Runs, aes(Season, Mean.x - Mean.y)) +
  geom_point(size=4) + geom_line(size=2) +
  ylab("Platoon Advantage") +
  labs(title="Ryan Howard's Platoon Advanatage") +
  theme(plot.title = element_text(size = rel(2))) +
  theme(axis.text = element_text(size = rel(2))) +
  theme(axis.title = element_text(size = rel(2))) )

# computes the fraction of PA against right-handed pitchers for
# each season

Merged.Runs$Fraction.Right <- with(Merged.Runs,
                                   round(PA.x / (PA.x + PA.y), 2))

print(Merged.Runs[, c("Season", "PA.x", "PA.y", "Fraction.Right")])