Box plot a distribution of sleeping habits

sleeping-habits.R

library("ggplot2")
library("reshape")

getData = function() {
  SOURCE=Sys.glob('/home/power/.thunderbird/*/*/*/*/Sent Mail')
  return(readLines(SOURCE))
}

getMatches = function(data) {
  matched_lines = grep('^Date:.*, .*-0\\d+', data, value=T)
  return(gsub('Date:.*, (.*-0\\d+).*', '\\1', matched_lines))
}

lines = getData()
matches = getMatches(lines)
dates = lapply(matches, function(f) {strptime(f, format="%d %b %Y %H:%M:%S %z")})
df = ldply(dates, unlist)
df$year = df$year + 1900
df_counts = count(df, vars=c("year", "hour"))

for (year in df_counts$year) {
  m = df_counts$year == year
  df_counts$freq[m] = df_counts$freq[m] / sum(df_counts$freq[m])
}

p = ggplot(df_counts, aes(x=year, y=hour)) +
  scale_x_continuous(limits=c(2004, 2012)) + 
  scale_y_datetime() +
  geom_tile(aes(fill=freq)) + 
  scale_fill_gradient()

show(p)