plot_by_day.R

library(ggplot2)
library(scales)

render_graph <- function(data) {
  ggplot(data=data, aes(x=date, y=value))  +
    geom_line(shape=1) +
    scale_x_datetime(labels = date_format("%m/%d %H:%M"))
}

library(xts)

sum_data <- function(data) {
  xtdata <- xts(data$value, data$date)
  xts_to_df(
    apply.daily(xtdata, sum)
  )
}

mean_data <- function(data) {
  xtdata <- xts(data$value, data$date)
  xts_to_df(
    apply.daily(xtdata, mean)
  )
}

xts_to_df <- function(x) {
  data.frame(
    date=index(x),
    value=as.numeric(coredata(x))
  )
}