I am working on building a shiny App. I have used some filters and rendered a data frame and the data frame changes dynamically as per the user input. But I cannot store a particular column value from a data frame into a vector. I need to store the reactive output every time into a vector so that I can use the values later again. Here the values are stored in text_vec and i need to pass that into the API but I cannot access the values from text_vec and i have to pass the updated values every time into the API
library(dplyr)
library(shiny)
shinyApp(ui = fluidPage(
sidebarLayout(
sidebarPanel(
selectInput(inputId = "cyl",
label = "Number cylinders:",
choices = c("all",sort(unique(mtcars$cyl))),
selected = "all"),
actionButton("capture",
"capture value")
), # closes sidebarPanel
mainPanel(
tableOutput("text"),
tableOutput("text2"),
tableOutput("text3"),
tableOutput("table")
) # closes mainPanel
) # closes sidebarLayout
), # closes fluidPage
server = function(input, output) {
# some example reactive data
cars_react <- reactive({
mtcars %>%
filter(cyl == input$cyl | input$cyl == "all")
})
# simply global assignment of a reactive vector
observeEvent(cars_react(), {
# here is a globally assigned vector taken from the reactive data
# reused in a render statement it will not react to change, since it is not reactive
test_vec3 <<- unique(cars_react()$hp)
})
# here a file is written to the working directory of your shiny app
# everytime cars_react() changes write (and overwrite) vector to a file
observeEvent(cars_react(), {
test_vec = unique(cars_react()$hp)
saveRDS(test_vec, file = "test_vec.Rdata")
})
# same as above but the file is gradually growing and not overwritten
# everytime cars_react() changes add vector to a (over several sessions growing) list
observeEvent(cars_react(), {
test_vec2 = unique(cars_react()$hp)
if (file.exists("test_list.Rdata")) {
temp = readRDS("test_list.Rdata")
test_list = c(temp, list(test_vec2))
} else {
test_list = list(test_vec2)
}
saveRDS(test_list, file = "test_list.Rdata")
})
# here we access the reactive data with isolate and make it non-reactive, but can update the values through a button click
text_vec <<- eventReactive(input$capture, {
isolate(unique(cars_react()$hp))
})
# output of our reactive data as table
output$table <- renderTable({
cars_react()
})
# text output of globally assigned non-reactive vector test_vec3 (not changing!)
output$text <- renderText({
test_vec3
})
# you can capture values of reactives with isolate, but then, they don't change anymore
# text output of isolated formely reactive vector unique(cars_react()$hp (not changing!)
output$text2 <- renderText({
isolate(unique(cars_react()$hp))
})
# text output of new reactive vector (changes when input$capture button is clicked)
output$text3 <- renderText({
text_vec()
})
for (i in text_vec)
{
url = "https://oscar.com/prweb/PRRestService/"
parameters<-'{
{
"Reference":"Account"
,"ReferenceValue":""
}'
b<-fromJSON(parameters)
b["ReferenceValue"]=i
r <- POST(url, body = parameters,encode = "json")
r_c<-toJSON(content(r))
print(r_c)
}
}
)
