#Chad Williamson

#this script anaylzes and clusters the individual seasons of
#all quarterbacks across every season in the NFL. Each season will be clustered
#by the metrics of: yardage, touchdowns, and interceptions.


#load cluster package
library(cluster)

#library used for visualization
library(factoextra)

#load data set
nflData <- read.csv("nflPassingData.csv", header = TRUE)

#remove any missing values
nflData <- na.omit(nflData)

#remove Name column for clustering
nflData.features = nflData
nflData.features$Name <- NULL

#determine optimal number of clusters
fviz_nbclust(nflData.features, kmeans, method = "wss")

#run k-means clustering with 5 clusters
clusters <- kmeans(nflData.features, 5,nstart = 25)

#create table for clusters generated. Useful for looking at individual seasons
print(table(nflData$Name, clusters$cluster))

#show cluster info
print(clusters)

#plot clusters
par(mfrow=c(1,3))
plot(nflData[c("Passing_Yards","TD_Passes")], col = clusters$cluster, main = "Passing Yards vs Touchdowns")
plot(nflData[c("Passing_Yards","Ints")], col = clusters$cluster, main = "Passing Yards vs Interceptions")
plot(nflData[c("TD_Passes","Ints")], col = clusters$cluster, main = "Touchdowns vs Interceptions")