问题
I am trying to use Shiny and ggvis to:
1) upload a data set
2) have the user select 2 columns (x, y)
3) return a ggvis plot displaying (x, y) from the uploaded data set
I've tried editing the examples from the Shiny Interactivity page as well as the movie explorer example. However, no chart is displayed.
I think my issue is around uploading the data set, but I don't know where to begin... Any suggestions?
Note - I've also tried this using rCharts, but I run into similar problems where no chart is displayed.
server.R
library(shiny)
library(dplyr)
library(ggvis)
shinyServer(function(input, output, session) {
fileHeaderNames <- reactive({
infile <- input$datfile
if(is.null(infile))
return(NULL)
d <- read.csv(infile$datapath, header = T)
return(names(d))
})
# dynamic variable names
observe({
updateSelectInput(session, 'x', choices = fileHeaderNames())
updateSelectInput(session, 'y', choices = fileHeaderNames())
}) # end observe
# uploading data set
theData <- reactive({
validate(
need(input$datfile != "", "Please upload a file")
)
infile <- input$datfile
dat <- read.csv(infile$datapath,
header = T,
stringsAsFactors = F)
if(is.null(infile)) return(NULL)
data.frame(x = dat[, input$x],
y = dat[, input$y])
})
# A simple visualisation. In shiny apps, need to register observers
# and tell shiny where to put the controls
theData %>%
ggvis(~x, ~y) %>%
layer_points() %>%
bind_shiny("plot", "plot_ui")
})
ui.R
library(ggvis)
library(shiny)
shinyUI(pageWithSidebar(
div(),
sidebarPanel(
fileInput('datfile', ''),
selectInput('x', 'x:' ,'x'),
selectInput('y', 'y:', 'y'),
uiOutput("plot_ui")
),
mainPanel(
ggvisOutput("plot")
)
))
回答1:
Here is an attempt, I added a couple of reactive blocks to get the names that should be added on the plot axis.
A trick you can use is to create a filtered dataframe that has two columns x
and y
and that changes when the user changes the values in the selectInput
. You can then tell ggvis
to plot x
and y
from that filtered dataframe and the plot will be interactive.
library(shiny)
library(dplyr)
library(ggvis)
shinyServer(function(input, output, session) {
#load the data when the user inputs a file
theData <- reactive({
infile <- input$datfile
if(is.null(infile))
return(NULL)
d <- read.csv(infile$datapath, header = T)
d
})
# dynamic variable names
observe({
data<-theData()
updateSelectInput(session, 'x', choices = names(data))
updateSelectInput(session, 'y', choices = names(data))
}) # end observe
#gets the y variable name, will be used to change the plot legends
yVarName<-reactive({
input$y
})
#gets the x variable name, will be used to change the plot legends
xVarName<-reactive({
input$x
})
#make the filteredData frame
filteredData<-reactive({
data<-isolate(theData())
#if there is no input, make a dummy dataframe
if(input$x=="x" && input$y=="y"){
if(is.null(data)){
data<-data.frame(x=0,y=0)
}
}else{
data<-data[,c(input$x,input$y)]
names(data)<-c("x","y")
}
data
})
#plot the ggvis plot in a reactive block so that it changes with filteredData
vis<-reactive({
plotData<-filteredData()
plotData %>%
ggvis(~x, ~y) %>%
layer_points() %>%
add_axis("y", title = yVarName()) %>%
add_axis("x", title = xVarName()) %>%
add_tooltip(function(df) format(sqrt(df$x),digits=2))
})
vis%>%bind_shiny("plot", "plot_ui")
})
EDIT: added tooltips.
来源:https://stackoverflow.com/questions/28176944/create-dynamic-ggvis-chart-from-uploaded-file-in-shiny