在 Rmarkdown 中使用 Shiny 创建反应式 selectInput - flexdashboard

Question

i'm using shiney for the first time. I want to create a reactive widget containing the names of the cities of interest for my study. When selecting cities, the rendered graph must change.

This is my imported csv:

```{r}
    Data20 = read_delim("SAC55.csv", delim = ",")
    tail(Data20)
```
   `DIAS `    `SANTOAMARO ` ` CACHOEIRA ` `CDA ` `SAUBARA `   SFC
  <date>             <dbl>         <dbl>  <dbl>      <dbl> <dbl>
1 2020-08-10           690           333    466         47   668
2 2020-08-11           695           335    470         47   676
3 2020-08-12           717           350    483         48   687
4 2020-08-13           719           356    500         48   701
5 2020-08-14           736           370    507         49   708
6 2020-08-15           763           377    527         49   713


```{r}
colnames(Data20) <- gsub(" ","",colnames(Data20))

```
DIAS       SANTOAMARO CACHOEIRA   CDA SAUBARA   SFC
  <date>          <dbl>     <dbl> <dbl>   <dbl> <dbl>
1 2020-08-10        690       333   466      47   668
2 2020-08-11        695       335   470      47   676
3 2020-08-12        717       350   483      48   687
4 2020-08-13        719       356   500      48   701
5 2020-08-14        736       370   507      49   708
6 2020-08-15        763       377   527      49   713

that's the way i'm trying to create a reactive selectImput

Data20 = read_delim("SAC55.csv", delim = ",")
colnames(Data20) <- gsub(" ","",colnames(Data20))
Data20$DIAS = as.Date(Data20$DIAS)



  ```{r}

ui = shinyUI(fluidPage(
  sidebarLayout(
    sidebarPanel(
selectInput(inputId = "Cidades", 
              label = "Cidades",
             choices = c("Santo Amaro" = "SANTOAMARO", "Cachoeira" = "CACHOEIRA", "Cruz das Almas" = "CDA", "Saubara" = "SAUBARA", "SFC" = "SFC"), 
             selected = "SANTOAMARO")),

mainPanel(plotlyOutput("city")))

  ))

server = shinyServer(function(input, output) {

  II <- reactive({
    Data20[ , c("DIAS", input$Cidades)]
     })

output$city = renderPlotly({
   ggplotly(ggplot(data = II(), mapping = aes_string("DIAS", y = input$cidades),  group=1))+
  geom_line(size = 1, col="pink")+
  geom_point(size = 1, col="red" )+
  labs(x = "DIAS") + 
  labs(y = "CASOS")+
  scale_x_date(NULL, date_labels = "%d, %b", date_breaks = "3 days")+
  scale_y_continuous(limits = c(0, 800), breaks = c(0,10,20,40,60,80,100,120,140,180,160,200,220,240,260,280,300,320,340,360,380,400,420,440,460,480,500,520,540,560,580,600,620,640,660,680,700,720,740,760,780,800,900))+
  theme(plot.title = element_text(hjust = 0.5))+
  theme(text=element_text(family=" Arial ", size=9, face="bold"))+
  theme(axis.text.x = element_text(family="Arial", face="bold", size=10, angle=45)) 
 })
})
shinyApp(ui = ui,server = server)
```

Although the widget with the names of the cities appear the graphics are formed. I've tried several ways to resolve this to no avail. If anyone can help me I will be very grateful.

Answer 1

Felipe - looks like there may be a few things going on here.

If your II() reactive expression is to pull the date and city data from Data20 , then you may want (note the hard brackets):

Data20[ , c("DIAS", input$Cidades)] 

otherwise, it will think Data20 is a function.

Also, the sample data Data20 has column names such as "SAUBARA", but the selectInput choices refer to `SAUBARA ` (with back ticks and a space) - these need to be the same.

Finally, in ggplotly , if you want the y-axis to display the selected city, then you could try:

aes_string(x = "DIAS", y = input$Cidades, group = 1)

...and ggplotly should be called on a ggplot object.

library(shiny)
library(ggplot2)
library(plotly)

ui <- shinyUI(fluidPage(
  sidebarLayout(
    sidebarPanel(
      selectInput(inputId = "Cidades", 
                  label = "Cidades:",
                  choices = c("Santo Amaro" = "SANTOAMARO", "Cachoeira" = "CACHOEIRA", "Cruz das Almas" = "CDA", "Saubara" = "SAUBARA", "SFC" = "SFC"), 
                  selected = "SANTOAMARO")),
    
    mainPanel(plotlyOutput("city")))
))

server <- shinyServer(function(input, output) {
  
  II <- reactive({ 
    Data20[ , c("DIAS", input$Cidades)]
  })
  
  output$city = renderPlotly({
    ggplotly(ggplot(data = II(), mapping = aes_string(x = "DIAS", y = input$Cidades, group = 1)) +
      geom_line(size = 1, col="pink")+
      geom_point(size = 1, col="red" )+
      labs(x = "DIAS",  tail(129)) + 
      labs(y = "CASOS")+
      scale_x_date(NULL, date_labels = "%d, %b", date_breaks = "3 days")+
      scale_y_continuous(limits = c(0, 800), breaks = c(0,10,20,40,60,80,100,120,140,180,160,200,220,240,260,280,300,320,340,360,380,400,420,440,460,480,500,520,540,560,580,600,620,640,660,680,700,720,740,760,780,800,900))+
      theme(plot.title = element_text(hjust = 0.5))+
      theme(text=element_text(family=" Arial ", size=9, face="bold"))+
      theme(axis.text.x = element_text(family="Arial", face="bold", size=10, angle=45)))
  })
  
})

shinyApp(ui, server)