How to render multiple values in ggplot title in a Shiny app? - r

Question

I'm having some problems with my ggplot title in this Shinyapp. I'm comparing countries and I want the countries the plot shows (colour = input$stat) to also be visible in the ggplot title. With the current code I'm only getting the first one. Is there perhaps an elegant solution to this problem?
If I'm comparing France, The United Kingdom and Spain, I want the title to be:
"Coronalandskampen, France, The United Kingdom, Spain"
library(tidyverse)
library(readxl)
library(httr)
library(zoo)
library(caTools)
library(shiny)
library(data.table)
#Get data
url <- paste("https://www.ecdc.europa.eu/sites/default/files/documents/COVID-19-geographic-disbtribution-worldwide-",format(Sys.time(), "%Y-%m-%d"), ".xlsx", sep = "")
GET(url, authenticate(":", ":", type="ntlm"), write_disk(tf <- tempfile(fileext = ".xlsx")))
df <- read_excel(tf)
df <- df %>%
rename(land = countriesAndTerritories,
`Antal fall` = cases,
`Antal döda` = deaths) %>%
arrange(land, dateRep) %>%
group_by(land) %>%
mutate(`Antal döda, kumulativt` = cumsum(`Antal döda`),
`Antal fall, kumulativt` = cumsum(`Antal fall`)) %>%
ungroup() %>%
filter(`Antal döda, kumulativt` > 10) %>%
group_by(land) %>%
mutate(antal_dagar = row_number(),
start_datum = min(dateRep),
`Antal Fall, rullande medeltal över sju dagar` = rollmean(`Antal fall`, 7, fill = NA),
`Antal döda, rullande medeltal över sju dagar` = rollmean(`Antal döda`, 7, fill = NA)) %>%
ungroup() %>%
mutate(`Döda per 100 000 invånare` = `Antal döda, kumulativt` * 100000 / popData2019) %>%
select(land, antal_dagar, `Antal fall`, `Antal fall, kumulativt`, `Antal döda`, `Antal döda, kumulativt`, `Döda per 100 000 invånare`,
`Antal Fall, rullande medeltal över sju dagar`, `Antal döda, rullande medeltal över sju dagar`, start_datum, geoId)
ui <- fluidPage(
navbarPage("Statistik Covid-19",
sidebarLayout(
sidebarPanel(
selectInput("stat", "Välj länder:", choices = unique(df$land), selected = "Sweden", multiple = TRUE),
varSelectInput("var", "Variabel:", df[c(3,4,5,6,7, 8, 9)])),
mainPanel(plotOutput("covid"))
)))
server <- function(input, output, session) {
df_graf <- reactive({df %>%
req(input$stat) %>%
filter(land %in% input$stat)
})
output$covid <- renderPlot({
ggplot(df_graf(), aes(antal_dagar, df_graf()[[input$var]], colour = land)) +
geom_line(size = 1.25) +
theme_Skane() +
labs(title = paste0("Coronalandskampen, ", input$stat),
x = "Antal dagar sedan 10:e dödsfallet",
y = as.name(input$var),
colour = NULL,
caption = "Source: European Centre for Disease Prevention and Control")
})
}
shinyApp(ui, server)

Answer 1

So basically, your question boils down to making sure that:
title = paste0("Coronalandskampen, ", input$stat)
returns the string "Coronalandskampen, France, The United Kingdom, Spain".
When running:
> paste0("Coronalandskampen, ", c("A", "B", "C", "D"))
[1] "Coronalandskampen, A" "Coronalandskampen, B"
[3] "Coronalandskampen, C" "Coronalandskampen, D"
We see that the result is a character vector with more than one element. The labsfunction uses only the first element of this vector. Therefore you need to build a single string.
Lets try this:
> paste0("Coronalandskampen, ", paste0(c("A", "B", "C", "D"), collapse = ", "))
[1] "Coronalandskampen, A, B, C, D"
So, in your code you can write:
title = paste0("Coronalandskampen, ", paste0(input$stat, collapse = ", "))