Rshiny: Make reactive plot with data from reactive function

Question

I'm making a shiny app in an Rmarkdown file using flexdashboard and I'm having trouble making a ggplot with data from a reactive function.

These are the steps/elements:

Get input from radiobuttons asking for a date, and print the answer (to check if he reacts fine) -> works
Reactive function reading the relevant csv-file (based on the date) and printing it's contents (to check) -> works
ggplot made with the contents of the csv-file -> does not work

When I use renderPlot() to make a ggplot with a non-reactive dataset (I loaded one), I get the correct result, so the ggplot-part is fine.

It has something to do with the reactive en renderPlot combinations, but I can't seem to figure it out. Although it's an "easy" concept, I keep having problems grasping the workflow, despite watching several movies and reading several guides.

This is my current code:

---
title: "Tests plot" 
output: 
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---

```{r setup, include=FALSE}
library(flexdashboard)
library(shiny)
library(ggplot2)
```

Input {.sidebar}
======================================
```{r}
radioButtons("countdate",h3("Datum"), c("01-12-2017"="T1","06-12-2017"="T2","24-12-2017"="T3"))
```

Data
======================================
Column
-----------------------------------------------------------------------
### Date
```{r}
reactive({ #OK
  input$countdate
})
```

Column
-----------------------------------------------------------------------
### Data
```{r}
fake2 <- reactive({read.csv2(paste(input$countdate, ".csv", sep = ""))})
fake2 #OK
```

Column
-----------------------------------------------------------------------
### Plot
```{r}
ggplot1 <- reactive({
  renderPlot({ggplot(fake2, aes(Rij, Plant)) +
      xlim(0,40) +
      ylim(0,50) +
      coord_equal() +
      geom_raster(aes(fill=Wtot)) +
      scale_fill_gradient(low="yellow", high="red")
    })
})

ggplot1
```

I also tried this in the plot-part:

renderPlot({
 ggplot(fake2, aes(Rij, Plant)) +
  xlim(0,40) +
  ylim(0,50) +
  coord_equal() +
  geom_raster(aes(fill=Wtot)) +
  scale_fill_gradient(low="yellow", high="red")
})

My data look like this:

Vplaat;Rij;Plant;Mtot;Wtot
A;4;10;2;20
B;4;46;5;35
C;9;5;1;14
D;9;30;0;42
E;11;17;8;85
...

Yep that's it. Another guy already answered that, but because I also needed to delete reactive() (which he didn't tell me, probably forgot to delete it in the code) it didn't work. Problem solved and thanks to you both! — Tingolfin
– Tingolfin, Commented Jan 15, 2018 at 10:40

Tingolfin · Accepted Answer · 2018-01-15 10:38:02Z

2

I got the answer thanks to a developer named Florian, but unfortunately he deleted his comment.

He told me I needed to use x() instead of x when working with reactive content, in my case: ggplot(fake2()... instead of ggplot(fake2...

This didn't work at first, but got me on the right track!

On top of that, I also had to remove reactive({}) around the renderPlot function and then it worked.

So thank you for your help Florian!

New code:

renderPlot({
 ggplot(fake2(), aes(Rij, Plant)) +
  xlim(0,40) + #rijen
  ylim(0,50) + #planten
  coord_equal() +
  geom_raster(aes(fill=Wtot)) +
  scale_fill_gradient(low="yellow", high="red")
})

answered Jan 15, 2018 at 10:38

Tingolfin

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1 Comment

Florian Over a year ago

Hi Tingolfin, sorry for deleting my answer, I do not have much experience with Shiny apps in this markdown-style, so I assumed my answer was just plain wrong. Glad that you were able to resolve your own issue!

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