Not getting graph in Shiny App in R - r

Question

I am trying to create small application using Shiny. Below is the data frame for which I am trying to create.
data<-data.frame(state=c('AZ','VA','CA','AZ','VA','CA'), city=c('Phoenix','Arlington','SantaClara','Mesa','Richmond','SF'),
avg=c(10,15,16,13,14,14), date=c('01/09/2017','01/10/2017','01/11/2017','02/09/2017','02/10/2017','02/10/2017'),stringsAsFactors = FALSE)
So, I am trying to create a graph between date(x-axis) and avg(y-axis). So this graph should change based on the selection from dropdown list of State.For example, for a particular selected state, it should show cities available(in other dropdown) in that state.
Below is my code:
library(shiny)
library(ggplot2)
library(plotly)
statelist<-as.list(data$state)
citylist<-as.list(data$city)
ui <- basicPage(
# plotOutput("plot1", click = "plot_click"),
# verbatimTextOutput("info")
sidebarPanel(
selectInput("plot1", label=h3("Select State"), choices = statelist),
selectInput("plot2", label=h3("Select City"), choices = citylist)
),
plotOutput(outputId="plot")
),
server <- function(input, output, session) {
observe(
{
state <- input$plot1
updateSelectInput(session, "plot2", choices = data$city[data$state == state])
}
),
output$plot<-renderPlot({
ggplot(data[data$city == input$plot2 &
data$state == input$plot1],aes(date,avg))
+geom_line()
})
}
shinyApp(ui, server)
Dropdown is working perfectly but not getting the graph.
Thanks in advance!!

Answer 1

I made some minor modifications to your code:
There were some commas in places where they should not be: after the ui constructor, and after the observe constructor.
There was a comma missing in data[data$city == input$plot2 &
data$state == input$plot1,]
I edited your observe to be an observeEvent
I modified the plot to show that it actually changes, since the sample data is quite limited.
Hope this helps!
library(shiny)
library(ggplot2)
library(plotly)
data<-data.frame(state=c('AZ','VA','CA','AZ','VA','CA'), city=c('Phoenix','Arlington','SantaClara','Mesa','Richmond','SF'),
avg=c(10,15,16,13,14,14), Date=c('01/09/2017','01/10/2017','01/11/2017','02/09/2017','02/10/2017','02/10/2017'),stringsAsFactors = FALSE)
statelist<-unique(data$state)
citylist<-unique(data$city)
ui <- basicPage(
# plotOutput("plot1", click = "plot_click"),
# verbatimTextOutput("info")
sidebarPanel(
selectInput("plot1", label=h3("Select State"), choices = statelist),
selectInput("plot2", label=h3("Select City"), choices = citylist)
),
plotOutput(outputId="plot")
)
server <- function(input, output, session) {
observeEvent(input$plot1,
{
state <- input$plot1
updateSelectInput(session, "plot2", choices = data$city[data$state == state])
}
)
output$plot<-renderPlot({
data = data[data$city == input$plot2 &
data$state == input$plot1,]
ggplot(data,aes(Date,avg)) + geom_point(size=5) + ggtitle(paste0(input$plot1," - ",input$plot2 ))
})
}
shinyApp(ui, server)