Using renderUI in Shiny to display vectors - html

Question

I want to be able to display a dynamic vector as text output in my Shiny app. I also want to utilize HTML (bold, font colors, etc.), so I am using htmlOutput and renderUI instead of textOutputand renderText per this suggestion.
Here is some example code:
library(shiny)
shinyApp(
ui <- htmlOutput("example"),
server <- function(input, output, session){
# vector (in the real app, this is not a static vector--it will be updated with other inputs)
states <- c("Alabama", "Alaska", "Arizona", "Arkansas")
# text output
output$example <- renderUI({
x <- paste0("<strong>Here are your states</strong>: ", states)
HTML(x)
}) #END RENDERUI
} #END SERVER
) #END SHINYAPP
The result of this code is:
Here are your states: Alabama Here are your states: Alaska Here are
your states: Arizona Here are your states: Arkansas
What I want is :
Here are your states: Alabama Alaska Arizona Arkansas
I have come up with a solution using conditional statements, but it's pretty clunky. Here's what I put in renderUI for the above desired output:
x <- paste0("<strong>Here are your states: </strong>",
if(!is.na(states[1])){states[1]},
if(!is.na(states[2])){states[2]},
if(!is.na(states[3])){states[3]},
if(!is.na(states[4])){states[4]})
HTML(x)
Again, the above solution works, but it's rather clunky and will be terribly inefficient for larger vectors (with, let's say, 10+ elements). Is there an easier way to display these vectors while still being able to utilize HTML?

Answer 1

You are looking for paste(..., collapse = " ").
library(shiny)
shinyApp(
ui <- htmlOutput("example"),
server <- function(input, output, session){
# vector (in the real app, this is not a static vector--it will be updated with other inputs)
states <- c("Alabama", "Alaska", "Arizona", "Arkansas")
# text output
output$example <- renderUI({
x <- paste0("<strong>Here are your states</strong>: ", paste(states, collapse = " "))
HTML(x)
}) #END RENDERUI
} #END SERVER
) #END SHINYAPP