R- Calculate a count of items over time using start and end dates

Question

I want to calculate a count of items over time using their Start and End dates.

Some sample data

START <- as.Date(c(\"2014-01-01\", \"2014-01-02\         


        

Answer 1

Using dplyr and foreach:

library(dplyr)
library(foreach)

df <- data.frame(START = as.Date(c("2014-01-01",
                                   "2014-01-02",
                                   "2014-01-03",
                                   "2014-01-03")),
                 END = as.Date(c("2014-01-04",
                                 "2014-01-03",
                                 "2014-01-03",
                                 "2014-01-04")))
df

r <- foreach(DATETIME = seq(min(df$START), max(df$END), by = 1),
             .combine = rbind) %do% {
  df %>%
    filter(DATETIME >= START & DATETIME <= END) %>%
    summarise(DATETIME, COUNT = n())
}
r