R Shiny ggplot reactive to dateRangeInput - r

Question

I am relatively new to R, and I'm trying to build a reactive ggplot in Shiny where the X-axis (dates) is reactive to a dateRangeInput in the UI. I've been googling everywhere, but every thing I try returns an error.
In the ggplot, the aes() calls from a dataset called datecorrected_totals, where x is the dates, and y=load are the two values that I would like to be reactive to the dateRangeInput so the ggplot will adjust the scale based on the period within the daterangeinput.
library(tidyverse)
library(shiny)
library(tidyr)
library(lubridate)
library(zoo)
data <- read_csv("--")
# Define UI ----
ui <- fluidPage(
titlePanel("--"),
sidebarLayout(
sidebarPanel(
h3("Calculator"),
dateRangeInput("dates", label = "Dates",
start = ("10-18-2018"),
end = max("05-29-2019"),
min = min("10-18-2018"),
max = max("05-29-2019"),
format = "mm-dd-yyyy"),
sliderInput("slider_a", label = "--",
min = 0,
max = 7,
value = 0),
sliderInput("slider_c", label = "--",
min = 7,
max = 42,
value = 7)
),
mainPanel(plotOutput('bar_chart'))
)
)
# Define server logic ----
server <- function(input, output, session) {
RE <- reactive({
})
output$bar_chart <- renderPlot(
ggplot(data = datecorrected_totals, aes(x = x, y = load)) +
geom_bar(stat = "identity")
)
}
# Run the app ----
shinyApp(ui = ui, server = server)

Answer 1

You need to filter the original dataset by the input dates. In this example data would be your original dataset.
RE <- reactive({
data %>%
filter(x>=input$dates[1] & x<=input$dates[2])
})
output$bar_chart <- renderPlot(
ggplot(data = RE(), aes(x = x, y = load)) +
geom_bar(stat = "identity")

Answer 2

There is no need to create a separate reactive() expression (unless required otherwise). The filter can be applied directly in renderPlot(). Thus, output$bar_chart becomes
output$bar_chart <- renderPlot(
datecorrected_totals %>%
filter(between(x, input$dates[1], input$dates[2])) %>%
ggplot(aes(x = x, y = load)) +
geom_bar(stat = "identity")
)
Below is a self-contained minimal reproducible example:
library(tidyverse)
library(lubridate)
library(shiny)
datecorrected_totals <- tibble(x = seq(as.Date("2018-10-18"), as.Date("2019-05-29"), length.out = 10L),
load = day(x))
# Define UI ----
ui <- fluidPage(
titlePanel("--"),
sidebarLayout(
sidebarPanel(
h3("Calculator"),
dateRangeInput("dates", label = "Dates",
start = mdy("10-18-2018"),
end = mdy("05-29-2019"),
min = mdy("10-18-2018"),
max = mdy("05-29-2019"),
format = "mm-dd-yyyy"),
),
mainPanel(plotOutput('bar_chart'))
)
)
# Define server logic ----
server <- function(input, output, session) {
output$bar_chart <- renderPlot(
datecorrected_totals %>%
filter(between(x, input$dates[1], input$dates[2])) %>%
ggplot(aes(x = x, y = load)) +
geom_col()
)
}
# Run the app ----
shinyApp(ui = ui, server = server)
Note that the date strings have been coerced to valid Date objects by calling mdy() to avoid error messages.
In addition, geom_bar(stat = "identity") has been replaced by geom_col().