Change numericInput value based on selected row - r

Question

I made a flowchart that changes based on numeric input the user provides. Now I want the user to be able to select a row from a table, and depending on what the user selected, the value of the numeric input changes.
In this example, selecting a movie title would change the numeric input "ticket price" based on a data frame with movie information. However, the user would be free to simply ignore the selectInput if they want to.
I already have the select input widget. I want it so that the widget reads the information of movie titles from the data frame with movie information.
I made this working example:
# Packages
library(shiny)
library(DiagrammeR) # creates flowchart
### Define UI ###
ui <- fluidPage(
# Sidebar with select input and numeric input
sidebarLayout(
sidebarPanel(h3("Flowchart creator with select Input"),
#User can choose movie title (optional)
selectInput(inputId = 'title',
label = "Movie title",
choices = c("","Matrix","Inception")),
#User can manually type in ticket price
numericInput("inputb",
"Ticket price is:",
value = 60)
),
# Show DiagrammeR plot
mainPanel(
grVizOutput("dg",width ="95%",height="95%")
)
)
)
### Define server ###
server <- function(input, output) {
#Creates tribble with movie information.
df <- as.data.frame(tribble(
~movie,~cost,~duration,
"Matrix",10.00,136,
"Inception",12.00,158,
"Titanic",15.00,194)) #end movie tribble
rv <<- reactive({
#Creates tibble. DiagrammeR reads values inside the tibble.
tibble::tibble(
price.tickets = input$inputb
) #End of tibble
})
#Define outputs to show in flowchart based on values on tibble
#The flowchart can't read inputs. It can only read values on the tibble.
output$price.tickets = renderText({rv()$price.tickets })
# Create flowchart with DOT language with DiagrammeR
output$dg <- renderGrViz({
grViz(diagram = "digraph flowchart {
legend [label = '##2']
price [label = '##1']
legend->price
}
[1]: rv()$price.tickets
[2]: 'ticket price'
") #end of flowchart in DOT language
})
}
# Run the application
shinyApp(ui = ui, server = server)
So it's two things:
Define selectInput choices based on the data.frame with movie information
Update the numericInput value based on the cost of the movie selected by the user, if the user chooses a movie.
Thank you!

Answer 1

We can combine datatable with updateNumericInput and updateSelectInput.
output$table_movies <- renderDT({
datatable(df,selection = 'single')
})
observeEvent(input$table_movies_rows_selected, {
rws <- input$table_movies_rows_selected
updateNumericInput(session = session,inputId = 'inputb',value = df[rws, 'cost'])
updateSelectInput(session = session, inputId = 'title', selected = df[rws, 'movie'])
})
Now every time a row is selected the inputs will "auto-select" that information and also trigger the flowchart to change.
App:
library(shiny)
library(DiagrammeR)
library(DT)
library(tidyverse)
#Creates tribble with movie information.
df <- as.data.frame(tribble(
~movie,~cost,~duration,
"Matrix",10.00,136,
"Inception",12.00,158,
"Titanic",15.00,194)) #end movie tribble
### Define UI ###
ui <- fluidPage(
# Sidebar with select input and numeric input
sidebarLayout(
sidebarPanel(h3("Flowchart creator with select Input"),
#User can choose movie title (optional)
selectInput(inputId = 'title',
label = "Movie title",
choices = df$movie),
#User can manually type in ticket price
numericInput("inputb",
"Ticket price is:",
value = 60),
DTOutput('table_movies')
),
# Show DiagrammeR plot
mainPanel(
grVizOutput("dg",width ="95%",height="95%")
)
)
)
### Define server ###
server <- function(input, output, session) {
rv <<- reactive({
#Creates tibble. DiagrammeR reads values inside the tibble.
tibble::tibble(
price.tickets = input$inputb
) #End of tibble
})
output$table_movies <- renderDT({
datatable(df,selection = 'single')
})
observeEvent(input$table_movies_rows_selected, {
rws <- input$table_movies_rows_selected
updateNumericInput(session = session,inputId = 'inputb',value = df[rws, 'cost'])
updateSelectInput(session = session, inputId = 'title', selected = df[rws, 'movie'])
})
#Define outputs to show in flowchart based on values on tibble
#The flowchart can't read inputs. It can only read values on the tibble.
output$price.tickets = renderText({rv()$price.tickets })
# Create flowchart with DOT language with DiagrammeR
output$dg <- renderGrViz({
grViz(diagram = "digraph flowchart {
legend [label = '##2']
price [label = '##1']
legend->price
}
[2]: 'ticket price'
") #end of flowchart in DOT language
})
}
# Run the application
shinyApp(ui = ui, server = server)