Shiny: Assigning different dataframe names in if-else statement - r

Question

I have reactive tables df1, df2 from Shiny. After some preprocessing I saved them as df1_a, df1_b, df1_a_grouped.
I have an if-else statement defined in df3:
if df1_b exists, then add 10 to column num1
else left_join(df2(), df_a_grouped()).
The script works. However, I would like to reference the two reactive dataframes defined in the if-else statement separately from df3 e.g., save as test1 for if else save as test2 so that I could use each of these in another if-else
Any help would be of great help.
Below is a fully reproducible sample script:
#### Libraries
library(shiny)
library(shinyWidgets)
library(tidyr)
library(dplyr)
library(shinydashboard)
library(reactable)
#### ui
ui <- dashboardPage(
dashboardHeader(title = "Skew"),
sidebar <- dashboardSidebar(
sidebarMenu(
menuItem("Test1", tabName = "tab1", icon = icon("table"))
)
),
body <- dashboardBody(
shinyjs::useShinyjs(),
tabItems(
tabItem(
tabName = "tab1",
fluidRow(
## df1
reactableOutput("table1"),
br(),
br(),
## df2
reactableOutput("table2"),
br(),
br(),
## df3
reactableOutput("table3")
) # fluidRow
) # tab1 - tabItem
) # tabItems
) # dashboardBody
) # dashboardPage
#### server #
server <- function(input, output, session) {
## df1
# reactive
df1 <- reactive({
data.frame(
# "id" = c("A", "A", "A", "B"),
"id" = c("A", "A", "A", "A"),
"num1" = c(10, 11, 12, 13)
)
})
# renderReactable
output$table1 <- renderReactable({
reactable(df1(), borderless = F, defaultColDef = colDef(align = "center"))
})
## df2
# reactive
df2 <- reactive({
data.frame(
"id" = c("A", "A", "B"),
"num2" = c(14, 15, 16)
)
})
# renderReactable
output$table2 <- renderReactable({
reactable(df2(), borderless = F, defaultColDef = colDef(align = "center"))
})
## df1_a
# reactive
df1_a <- reactive({
df1() %>% filter(id == "A")
})
## df1_b
# reactive
df1_b <- reactive({
df1() %>% filter(id == "B")
})
##
df1_a_grouped <- reactive({
df1_a() %>%
group_by(id) %>%
summarise(
sum_num1 = sum(num1)
)
})
## df3
# reactive
# would like to reference the two dataframes separately
df3 <- reactive({
if (nrow(df1_b()) > 0) {
df <- df1_b() %>% mutate(num1_addten = num1 + 10) # test1
} else {
df <- left_join(df2(), df 1 _a_grouped(), on = "id") # test2
}
return(df)
})
}
shinyApp(ui, server)

Answer 1

There are many ways to store reactive elements. You could make df3 a reactive object storing a list with your different dataframes:
df3 <- reactive({
if (nrow(df1_b()) > 0) {
df1 <- df1_b() %>% mutate(num1_addten = num1 + 10) # test1
} else {
df1 <- left_join(df2(), df1_a_grouped(), on = "id") # test2
}
df2 <- df1_b() %>% mutate(num1_addten = num1 + 10)
df3 <- left_join(df2(), df1_a_grouped(), on = "id")
list(df1, df2, df3)
})
Then you can call them like this:
df3()[[1]]
df3()[[2]]
df3()[[3]]