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R code for "cleaning" Statcast data
# read in SC data from 2019 seasons
# through games of June 23, 2019
library(tidyverse)
library(CalledStrike)
sc2019 <- read_csv("~/Dropbox/2016 WORK/BLOG Baseball R/OTHER/StatcastData/statcast2019.csv")
sc2019_ip <- filter(sc2019, type == "X")
# focus on Statcast 2019 in-play data
# look for weird values of launch speed and launch angle
# first graph the distinct values of launch speed
sc2019_ip %>%
group_by(launch_speed) %>%
summarize(N = n()) %>%
ggplot(aes(launch_speed, N)) +
geom_col() +
increasefont() +
ggtitle("Distribution of 2019 Launch Speeds") +
centertitle()
# graph of the distinct values of launch angles
sc2019_ip %>%
group_by(launch_angle) %>%
summarize(N = n()) %>%
ggplot(aes(launch_angle, N)) +
geom_col() +
increasefont() +
ggtitle("Distribution of 2019 Launch Angles") +
centertitle()
# pick out the extreme pairs of (ls, la)
# finds the pairs where the frequency exceeds n_min
find_extreme <- function(d, n_min = 80){
d %>%
group_by(launch_speed, launch_angle) %>%
summarize(N = n()) -> S
S %>% filter(N >= n_min)
}
# decide on using a frequency of 100 as a cutoff
o19 <- find_extreme(sc2019_ip, n_min = 100) %>%
arrange(desc(N))
# remove these pairs from Statcast data
# must be a more elegant way of doing this
sc2019_ip %>% mutate(Row = row_number()) -> sc2019_ip
find_rows_one_pair <- function(j){
sc2019_ip %>%
filter(launch_speed == o19$launch_speed[j],
launch_angle == o19$launch_angle[j]) %>%
select(Row) %>% pull()
}
row_numbers <- NULL
for(j in 1:nrow(o19)){
row_numbers <- c(row_numbers, find_rows_one_pair(j))
}
sc2019_ip %>%
filter(!row_number() %in% row_numbers) ->
sc2019_clean
# graphs of cleaned data
sc2019_clean %>%
group_by(launch_speed) %>%
summarize(N = n()) %>%
ggplot(aes(launch_speed, N)) +
geom_col() +
increasefont() +
ggtitle("Distribution of 2019 Launch Speeds") +
centertitle()
# graph of launch angles from cleaned data
sc2019_clean %>%
group_by(launch_angle) %>%
summarize(N = n()) %>%
ggplot(aes(launch_angle, N)) +
geom_col() +
increasefont() +
ggtitle("Distribution of 2019 Launch Angles") +
centertitle()
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