I'm trying to add a dynamic ggvis plot to a Shiny app. First, user picks a dimension, and then adds items from that dimension.
For global.R and sample data, see https://gist.github.com/tts/a41c8581b9d77f131b31
server.R:
shinyServer(function(input, output, session) {
# Render a selectize drop-down selection box
output$items <- renderUI({
selectizeInput(
inputId = 'items',
label = 'Select max 4. Click to delete',
multiple = TRUE,
choices = aalto_all[ ,names(aalto_all) %in% input$dim],
options = list(maxItems = 4, placeholder = 'Start typing')
)
})
selected <- reactive({
if (is.null(input$items)) {
return(aalto_all)
}
df <- aalto_all[aalto_all[[input$dim]] %in% input$items, ]
df$keys <-seq(1, nrow(df))
df
})
selected %>%
ggvis(~WoS, ~NrOfAuthors, fill = ~School, key := ~keys) %>%
layer_points() %>%
add_tooltip(show_title) %>%
bind_shiny("gv")
show_title <- function(x=NULL) {
if(is.null(x)) return(NULL)
key <- x["keys"][[1]]
selected()$Title20[key]
}
})
ui.R:
shinyUI(fluidPage(
titlePanel('Some (alt)metric data for articles published since 2010'),
sidebarLayout(
sidebarPanel(
selectInput(
inputId = "dim",
label = "Dimension",
choices = dimensions,
selected = c("Title")),
uiOutput("items")
),
mainPanel(
tabsetPanel(
# I'll add more tabs
tabPanel("Plot with ggvis", ggvisOutput("gv"))
)
)
)
))
This is OK
- in the beginning, when there are no items selected, and all data is plotted. This is a hack because the ggvis object throws an error if there is no data served.
- when all selected items are deleted (which is the same as 1.) and another dimension is chosen
But when I try to switch to another dimension without deleting the items first, I get this:
Error in `$<-.data.frame`(`*tmp*`, "keys", value = c(1L, 0L)) :
replacement has 2 rows, data has 0
I understand that ggvis is very new and constantly developing, but I suspect that there is merely something in Shiny reactive values that is out of sync. If anyone could point out what I'm doing wrong, thanks a lot!
The error is caused because you have a data.frame with zero rows and have a resulting 1:0.
You can change your selected function to:
selected <- reactive({
if (is.null(input$items)) {
return(aalto_all)
}
df <- aalto_all[aalto_all[[input$dim]] %in% input$items, ]
df$keys <-seq_along(df[,1])
if(nrow(df) == 0){
return(aalto_all)
}
df
})
来源：https://stackoverflow.com/questions/24554734/dynamic-ggvis-object-in-shiny