Styjun

I've looked through R Shiny tutorials and stackoverflow for answers related to my query. I usually wait for 3-4 days to solve a coding problem before I attempt to post.

I have an animated slider in my UI that loops through time interval in a column (column a) . I'm trying to produce an animated line plot that plots y values of another column (column b), corresponding to the nrow() of that time interval. The slider works perfectly, but I haven't been able to plot the output.

I mightve missed some concepts related to reactivity in Shiny app. Appreciate any guidance I can get related to my query. I'll be happy to post more info if needed.

a <- c(0,1,2,3,4,5,6) 
b <- c(50,100,40,30,20,80) 

mydata <- cbind(a,b) 
mydata <- as.data.frame(mydata())

ui <- fluidPage (

 headerPanel("basic app"),

 sidebarPanel(

 sliderInput("slider",
 label = "Time elapsed",
 min = 0,
 max = nrow(mydata()),
 value = 1, step = 1,
 animate =
 animationOptions(interval = 200, loop = TRUE))
 ),
 mainPanel(
 plotlyOutput("plot")
 )
)

server <- function(input, output) 
 sliderValues <- reactive(
 data.frame(
 Name = "slider",
 Value = input$slider)
 )
 output$plot <- renderPlot(
 x<- as.numeric(input$slider)
 y <- as.numeric(b[x])
 ggplot(mydata,aes_string(x,y))+ geom_line()
 )

Just as a demo, I wanted the animated plot to come out like this, but in correspondance to UI slider values :

library(gganimate)
library(ggplot2)
fake <- c(1,10)
goods <- c(11,20)
fakegoods <- cbind(fake,goods)
fakegoods <- data.frame(fakegoods)
ggplot(fakegoods, aes(fake, goods)) + geom_line() + transition_reveal(1, fake)

Does this accomplish what you are looking for? Note that I removed the first element, 0, from vector a as your original example had more elements in a than b, and in order for them to be cbind together they must be the same length.

library(ggplot2)
library(shiny)

a <- c(1,2,3,4,5,6) 
b <- c(50,100,40,30,20,80) 

mydata <- cbind(a,b) 
mydata <- as.data.frame(mydata)

ui <- fluidPage (

 headerPanel("basic app"),

 sidebarPanel(

 sliderInput("slider",
 label = "Time elapsed",
 min = min(mydata$a),
 max = max(mydata$a),
 value = min(mydata$a), step = 1,
 animate =
 animationOptions(interval = 200, loop = TRUE))
 ),
 mainPanel(
 plotOutput("plot")
 )
)

server <- function(input, output) 
 output$plot <- renderPlot(
 plotdata <- mydata[1:which(input$slider==mydata$a),]
 p <- ggplot(plotdata,aes(x = a,y = b))

 if(nrow(plotdata)==1) 
 p + geom_point()
 else 
 p + geom_line()
 

 )