firmo23
Reputation: 8404
Shiny app breaks down when I choose specific coordinates in a ggplot
I have a shiny app which creates a scatter plot between selected variables of the mtcars dataset. As you can see I have modified the data labels in order to display the car type in every point instead of the x-y coordinates. The problem is that when I click on my trendline, on spots where there are no data -so the coordinates are displayed-the app is breaking down. Here is a reproducible example:
#ui.r
library(shiny)
library(ggplot2)
library(plotly)
library(dplyr)
fluidPage(
# App title ----
titlePanel(div("CROSS CORRELATION",style = "color:blue")),
# Sidebar layout with input and output definitions ----
sidebarLayout(
# Sidebar panel for inputs ----
sidebarPanel(
),
# Main panel for displaying outputs ----
mainPanel(
tabsetPanel(type = "tabs",
tabPanel("Correlation Plot",
fluidRow(
column(3, uiOutput("lx1")),
column(3,uiOutput("lx2"))),
hr(),
fluidRow(
tags$style(type="text/css",
".shiny-output-error { visibility: hidden; }",
".shiny-output-error:before { visibility: hidden; }"
)
),
fluidRow(
plotlyOutput("sc"))
)
)
)))
#server.r
function(input, output) {
output$lx1<-renderUI({
selectInput("lx1", label = h4("Select 1st Expression Profile"),
choices = colnames(mtcars[,2:5]),
selected = "Lex1")
})
output$lx2<-renderUI({
selectInput("lx2", label = h4("Select 2nd Expression Profile"),
choices = colnames(mtcars[,2:5]),
selected = "Lex2")
})
# 1. create reactive values
vals <- reactiveValues()
# 2. create df to store clicks
vals$click_all <- data.frame(x = numeric(),
y = numeric(),
label = character())
# 3. add points upon plot click
observe({
# get clicked point
click_data <- event_data("plotly_click", source = "select")
# get data for current point
label_data <- data.frame(x = click_data[["x"]],
y = click_data[["y"]],
label = click_data[["key"]],
stringsAsFactors = FALSE)
# add current point to df of all clicks
vals$click_all <- merge(vals$click_all,
label_data,
all = TRUE)
})
output$sc<-renderPlotly({
mtcars$car <- row.names(mtcars)
p1 <- ggplot(mtcars, aes_string(x = input$lx1, y = input$lx2,key = "car",group="car"))+
# Change the point options in geom_point
geom_point(color = "darkblue") +
# Change the title of the plot (can change axis titles
# in this option as well and add subtitle)
labs(title = "Cross Correlation") +
# Change where the tick marks are
# Change how the text looks for each element
theme_bw()+
geom_smooth(aes(group = 1))+
# 4. add labels for clicked points
geom_text(data = vals$click_all,
aes(x = x, y = y, label = label),
inherit.aes = FALSE, nudge_x = 0.25)
ggplotly(p1,source = "select", tooltip = c("key")) %>%
layout(hoverlabel = list(bgcolor = "white",
font = list(family = "Calibri",
size = 9,
color = "black")))
})
}
Upvotes: 1
Views: 99
Answers (1)
Michal Majka
Reputation: 5471
As you said, the app breaks down after clicking on the trend line where there is no point that corresponds to a car. Let us stick to that scenario. You get following error:
Warning: Error in data.frame: arguments imply differing number of rows: 1, 0
The reason for this error is that after clicking on the trend line the data frame stored in click_data variable does not contain variable key.
You try to access this variable anyway via click_data[["key"]] and the output of it is NULL as it is not existent.
In the next step you want to build a new data.frame label_data, where label is assigned to NULL and hence the error.
label_data <- data.frame(x = click_data[["x"]], # it is fine because it is number
y = click_data[["y"]], # also fine
label = NULL, # label gets NULL
stringsAsFactors = FALSE)
We can simply reproduce this error with
> data.frame(x = 1, y = 1, label = NULL)
Error in data.frame(x = 1, y = 1, label = NULL) :
arguments imply differing number of rows: 1, 0
Now that we know why we get the error, we can find multiple solutions to it. One of them would be to require first that
click_data <- event_data("plotly_click", source = "select")
returns a data frame and then if it does not contain key variable, we set the value of label to "" with
label_ <- ifelse(is.null(click_data[["key"]]),
yes = "",
no = click_data[["key"]])
That is
observe({
# get clicked point
click_data <- event_data("plotly_click", source = "select")
# Require that click_data is available (does not return NULL)
req(click_data)
label_ <- ifelse(is.null(click_data[["key"]]),
yes = "",
no = click_data[["key"]])
# get data for current point
label_data <- data.frame(x = click_data[["x"]],
y = click_data[["y"]],
label = label_,
stringsAsFactors = FALSE)
# add current point to df of all clicks
vals$click_all <- merge(vals$click_all,
label_data,
all = TRUE)
})
Full code:
library(shiny)
library(ggplot2)
library(plotly)
library(dplyr)
ui <- fluidPage(
# App title ----
titlePanel(div("CROSS CORRELATION",style = "color:blue")),
# Sidebar layout with input and output definitions ----
sidebarLayout(
# Sidebar panel for inputs ----
sidebarPanel(
),
# Main panel for displaying outputs ----
mainPanel(
tabsetPanel(type = "tabs",
tabPanel("Correlation Plot",
fluidRow(
column(3, uiOutput("lx1")),
column(3,uiOutput("lx2"))),
hr(),
fluidRow(
tags$style(type="text/css",
".shiny-output-error { visibility: hidden; }",
".shiny-output-error:before { visibility: hidden; }"
)
),
fluidRow(
plotlyOutput("sc"))
)
)
)))
#server.r
server <- function(input, output) {
output$lx1<-renderUI({
selectInput("lx1", label = h4("Select 1st Expression Profile"),
choices = colnames(mtcars[,2:5]),
selected = "Lex1")
})
output$lx2<-renderUI({
selectInput("lx2", label = h4("Select 2nd Expression Profile"),
choices = colnames(mtcars[,2:5]),
selected = "Lex2")
})
# 1. create reactive values
vals <- reactiveValues()
# 2. create df to store clicks
vals$click_all <- data.frame(x = numeric(),
y = numeric(),
label = character())
# 3. add points upon plot click
observe({
# get clicked point
click_data <- event_data("plotly_click", source = "select")
# Require that click_data is available (does not return NULL)
req(click_data)
label_ <- ifelse(is.null(click_data[["key"]]),
yes = "",
no = click_data[["key"]])
# get data for current point
label_data <- data.frame(x = click_data[["x"]],
y = click_data[["y"]],
label = label_,
stringsAsFactors = FALSE)
# add current point to df of all clicks
vals$click_all <- merge(vals$click_all,
label_data,
all = TRUE)
})
output$sc<-renderPlotly({
mtcars$car <- row.names(mtcars)
p1 <- ggplot(mtcars, aes_string(x = input$lx1, y = input$lx2,key = "car",group="car"))+
# Change the point options in geom_point
geom_point(color = "darkblue") +
# Change the title of the plot (can change axis titles
# in this option as well and add subtitle)
labs(title = "Cross Correlation") +
# Change where the tick marks are
# Change how the text looks for each element
theme_bw()+
geom_smooth(aes(group = 1))+
# 4. add labels for clicked points
geom_text(data = vals$click_all,
aes(x = x, y = y, label = label),
inherit.aes = FALSE, nudge_x = 0.25)
ggplotly(p1,source = "select", tooltip = c("key")) %>%
layout(hoverlabel = list(bgcolor = "white",
font = list(family = "Calibri",
size = 9,
color = "black")))
})
}
shinyApp(ui, server)
Upvotes: 3
Related Questions
- Problems with reactive ggplot in Shiny
- Why does the same ggplot work direct but fail in Shiny?
- Ggplot2 displaying error message in shiny app
- Shiny App: Cannot Generate the Correct Plot with ggplot2
- Argument improper in shiny ggplot
- Interactive shiny app returns wrong coordinates
- R Shiny app with ggplot2 error
- Shiny and ggplot2 script issue
- R Shiny: not sure why ggplot is failing
- ggplot error in R shiny package