Interactive Bar Chart Using Shiny - Graph changes based on selected columns - r

Question

I am teaching myself r and shiny and trying to make an interactive bar chart where the user can change the chart based on columns. I keep getting errors with this code. Any help would be appreciated! My data has four columns: v, one, two, three. The first column is characters and the last three are numbers. I want to change the bar chart based on the y axis (columns: one, two and three). Right now, the error I am getting is: missing value where TRUE/FALSE needed.
library(shiny)
library(readr)
library(ggplot2)
data <- read.csv('scoring.csv')
data$v <- as.character(data$v)
ui <- fluidPage(
titlePanel("Scoring"),
sidebarPanel(
selectInput(inputId = "scoring", label = "Select a score:", c("Scoring Method 1", "Scoring Method 2", "Scoring Method 3"))),
mainPanel(
plotOutput(outputId = "bar")
)
)
#browser()
server <- function(input, output) {
new_data <- reactive({
selected_score = as.numeric(input$"scoring")
if (selected_score == "Scoring Method 1"){(data[data$one])}
if (selected_score == "Scoring Method 2"){(data[data$two])}
if (selected_score == "Scoring Method 3"){(data[data$three])}
})
#browser()
output$bar <- renderPlot({
newdata <- new_data()
p <- ggplot(newdata, aes(x=reorder(v, -selected_score), selected_score, y = selected_score, fill=v)) +
geom_bar(stat = 'identity', fill="darkblue") +
theme_minimal() +
ggtitle("Sports")
barplot(p, height = 400, width = 200)
})
}
Run the application
shinyApp(ui = ui, server = server)

Answer 1

You have a few errors in your code. In the server part, please use input$scoring, instead of input$"scoring".
First, in ui selectInput could be defined as
selectInput(inputId = "scoring", label = "Select a score:", c("Scoring Method 1"="one",
"Scoring Method 2"="two",
"Scoring Method 3"="three")))
Second, your reactive dataframe new_data() could be defined as shown below:
new_data <- reactive({
d <- data %>% mutate(selected_score = input$scoring)
d
})
Third, ggplot could be defined as
output$bar <- renderPlot({
newdata <- new_data()
p <- ggplot(newdata, aes(x=v, y = newdata[[as.name(selected_score)]], fill=v)) +
geom_bar(stat = 'identity', position = "dodge", fill="blue") +
theme_bw() +
#scale_fill_manual(values=c("blue", "green", "red")) +
scale_y_continuous(limits=c(0,10)) +
ggtitle("Sports")
p
})
Please note that you had an extra selected_score variable within aes. My suggestion would be to play with it to reorder x, and review some online or youtube videos on R Shiny.