create a graph showing the range over which the date are spread by each group with selection of category in R

I am new with R, I have a data.table in R which looks like:

> dt <- data.table(category = rep(c("0001", "0002", "0003"), c(10,3,4)), 
                  grp = c("01", "03", "04", "06", "81", "82", "83", "84", "85", "86", 
                          "01", "02", "03",
                          "01", "02", "03", "04"),
                  min_date = c("2012-04-18", "2012-04-18", "2012-04-23", "2012-04-10", "2012-04-05", 
                               "2012-04-13", "2012-04-10", "2012-04-07", "2012-04-19", "2012-04-05",
                               "2012-04-04", "2012-04-06", "2012-04-25", "2012-04-19", "2012-04-05",
                               "2012-04-26", "2012-04-27"),
                  max_date = c("2012-05-23", "2012-05-19", "2012-05-19", "2012-04-24", "2012-05-23", 
                               "2012-05-09", "2012-05-19", "2012-05-24", "2012-05-22", "2012-05-23",
                               "2012-05-12", "2012-05-11", "2012-05-17", "2012-05-22", "2012-05-22",
                               "2012-05-19", "2012-05-17"),
                  hours_played = c(426, 381, 318, 168, 583, 314, 477, 568, 398, 582, 458, 429, 268, 
                                   395, 568, 276, 238))

> dt
    category grp   min_date   max_date hours_played
 1:     0001  01 2012-04-18 2012-05-23          426
 2:     0001  03 2012-04-18 2012-05-19          381
 3:     0001  04 2012-04-23 2012-05-19          318
 4:     0001  06 2012-04-10 2012-04-24          168
 5:     0001  81 2012-04-05 2012-05-23          583
 6:     0001  82 2012-04-13 2012-05-09          314
 7:     0001  83 2012-04-10 2012-05-19          477
 8:     0001  84 2012-04-07 2012-05-24          568
 9:     0001  85 2012-04-19 2012-05-22          398
10:     0001  86 2012-04-05 2012-05-23          582
11:     0002  01 2012-04-04 2012-05-12          458
12:     0002  02 2012-04-06 2012-05-11          429
13:     0002  03 2012-04-25 2012-05-17          268
14:     0003  01 2012-04-19 2012-05-22          395
15:     0003  02 2012-04-05 2012-05-22          568
16:     0003  03 2012-04-26 2012-05-19          276
17:     0003  04 2012-04-27 2012-05-17          238

I want to create a visualization in order to show the range in which each group grp was active along with the corresponding hours_played . There should be a functionality to select the category from a drop down list .

on selecting a category from the drop down list of available categories, the graph should show the range of date in which all the groups belonging to that category were active, with hours played for that category alongside/inside. time axis must be X axis, time range can be by 10 days.

something like this: my paint skills are poor, but just tried to giev an idea of what I wanted.

How can I do this in R.

Solution

I propose you this plot:

library(ggplot2)
library(scales)
ggplot(dt) +
    aes(y = grp, x = as.Date(min_date)) +
    geom_segment(aes(yend = grp, 
                     xend = as.Date(max_date), 
                     color = grp), 
                 size = 5,
                 show.legend = FALSE) +

    geom_text(aes(label = paste0('grp', grp)), 
              nudge_x = 3,
              size = 3) +

    geom_text(aes(label = paste0(hours_played, ' h'), 
                  x = as.Date(max_date)), 
              nudge_x = 1.5,
              size = 2) +

    facet_grid(category ~ ., scales = 'free_y', labeller = label_both) +
    scale_x_date('Date', date_breaks = '10 days', expand = c(0, 2)) +
    scale_color_brewer(palette = 'Set3') +
    theme_bw() +
    theme(axis.line.y = element_blank(),
          axis.text.y = element_blank(),
          axis.ticks.y = element_blank())

The important bits are the three geom_* (one for the segment, and two for the texts) and the faceting (what divides the plot in three subplot, based on the category)

Update:

To add interaction to the plot we need a reactive environment. The simplest one is a .Rmd document.

Paste this into a new .Rmd file, and 'Run' it:

---
output: html_document
runtime: shiny

---

```{r data, echo = F}
dt <- data.frame(category = rep(c("0001", "0002", "0003"), c(10,3,4)), 
                  grp = c("01", "03", "04", "06", "81", "82", "83", "84", "85", "86", 
                          "01", "02", "03",
                          "01", "02", "03", "04"),
                  min_date = c("2012-04-18", "2012-04-18", "2012-04-23", "2012-04-10", "2012-04-05", 
                               "2012-04-13", "2012-04-10", "2012-04-07", "2012-04-19", "2012-04-05",
                               "2012-04-04", "2012-04-06", "2012-04-25", "2012-04-19", "2012-04-05",
                               "2012-04-26", "2012-04-27"),
                  max_date = c("2012-05-23", "2012-05-19", "2012-05-19", "2012-04-24", "2012-05-23", 
                               "2012-05-09", "2012-05-19", "2012-05-24", "2012-05-22", "2012-05-23",
                               "2012-05-12", "2012-05-11", "2012-05-17", "2012-05-22", "2012-05-22",
                               "2012-05-19", "2012-05-17"),
                  hours_played = c(426, 381, 318, 168, 583, 314, 477, 568, 398, 582, 458, 429, 268, 
                                   395, 568, 276, 238))
```

```{r graph, echo = F}
library(ggplot2)
library(scales)

selectInput('category','Choose the category:', choices = unique(dt$category))

dt_filtered <- reactive({
  dt[dt$category == input$category, ]
})

renderPlot({
  ggplot(dt_filtered()) +
    aes(y = grp, x = as.Date(min_date)) +
    geom_segment(aes(yend = grp, 
                     xend = as.Date(max_date), 
                     color = grp), 
                 size = 5,
                 show.legend = FALSE) +

    geom_text(aes(label = paste0('grp', grp)), 
              nudge_x = 3,
              size = 3) +

    geom_text(aes(label = paste0(hours_played, ' h'), 
                  x = as.Date(max_date)), 
              nudge_x = 1.5,
              size = 2) +
    scale_x_date('Date', date_breaks = '10 days', expand = c(0, 2)) +
    scale_color_brewer(palette = 'Set3') +
    theme_bw() +
    theme(axis.line.y = element_blank(),
          axis.text.y = element_blank(),
          axis.ticks.y = element_blank())

})
```