r-使用操作按钮上传csv文件并显示corrplot

Question

我试图用R:：shine制作一个web应用程序，但我遇到了一段代码的问题。事实上，我想上传一个csv文件并显示一个相关图。

我试着用actionbutton((和updateSelectizeInput((设置相关图

但是出现了一个错误：

错误：不支持的索引类型：NULL

有人有解决方案吗？感谢

注意-我不想使用fileInput小部件上传csv文件！只能通过操作按钮！

library(shiny)
library(readr)
library(corrplot)
library(DT)

# File used for the example
data(iris)
write.csv(x = iris, file = "iris.csv")

#UI
ui <- shinyUI(
fluidPage(
navbarPage(
id = "navbar",
tabPanel(
title = "UPLOAD",
br(),
actionButton(inputId = "file", label = "ADD A FILE")
)
)
)
)
#SERVER
server <- function(input, output, session) {
path <- reactiveValues(pth = NULL)
file.choose2 <- function(...) {
pathname <- NULL;
tryCatch({
pathname <- file.choose();
}, error = function(ex) {
})
pathname;
}
observeEvent(input$file,{
path$pth <- file.choose2()
})
observeEvent(input$file,  {
newvalue <- "B"
updateNavbarPage(session, "navbar", newvalue)
})
data <- reactive({
df <- readr::read_csv(file = path$pth)
return(df)
})
observeEvent(input$file,  {
appendTab(
inputId = "navbar",
tabPanel(
value = "B",
title = "Corr",
sidebarLayout(
sidebarPanel(
selectizeInput(
inputId = "select04",
label = "Select features",
choices = NULL,
multiple = TRUE)
),
mainPanel(
plotOutput(
outputId = "corrplot01", height = "650px")
)
)
)
)
}, once = TRUE)
# I suppose there is a problem with this line
observeEvent(input$select04, { 
col <- names(data())
col.num <- which(sapply(data(), class) == "numeric")
col <- col[col.num]
updateSelectizeInput(session = session, inputId = "select04", choices = col)
})
output$corrplot01 <- renderPlot({ 
df <- data()
df1 <- df[,input$select04]
corr <- cor(x = df1, use  = "pairwise.complete.obs")
corrplot(corr = corr, 
title = "")
})
}
shinyApp(ui, server)

Answer 1

我对您的ui和服务器做了一些更改，但我认为这可能会解决您的问题。

我从服务器上删除了observeEvent(input$file, ...{})，并直接在ui中添加了ui部分。

我还在data反应性呼叫中添加了3个req()呼叫，在第二个observeEvent(input$select04, ...{})(我将其更改为正常observe(和renderPlot呼叫中添加。

library(shiny)
library(readr)
library(corrplot)
library(DT)

# File used for the example
data(iris)
write.csv(x = iris, file = "iris.csv", row.names = F)

#UI
ui <- shinyUI(
fluidPage(
navbarPage(
id = "navbar",
tabPanel(
title = "UPLOAD",
br(),
actionButton(inputId = "file", label = "ADD A FILE"),
tabPanel(
value = "B",
title = "Corr",
sidebarLayout(
sidebarPanel(
selectizeInput(width = "300px",
inputId = "select04",
label = "Select features",
choices = NULL,
multiple = TRUE)
),
mainPanel(
plotOutput(
outputId = "corrplot01", height = "650px")
)
)
)
)
)
)
)
#SERVER
server <- function(input, output, session) {
path <- reactiveValues(pth = NULL)
file.choose2 <- function(...) {
pathname <- NULL;
tryCatch({
pathname <- file.choose();
}, error = function(ex) {
})
pathname;
}
observeEvent(input$file,{
path$pth <- file.choose2()
})
observeEvent(input$file,  {
newvalue <- "B"
updateNavbarPage(session, "navbar", newvalue)
})
data <- reactive({
req(path$pth)
df <- readr::read_csv(file = path$pth)
return(df)
})

# I suppose there is a problem with this line
observe({ 
req(names(data()))
col <- names(data())
col.num <- which(sapply(data(), class) == "numeric")
col <- col[col.num]
updateSelectizeInput(session = session, inputId = "select04", choices = col)
})
output$corrplot01 <- renderPlot({ 
req(input$select04)
df <- data()
df1 <- df[,input$select04]
corr <- cor(x = df1, use  = "pairwise.complete.obs")
corrplot(corr = corr, 
title = "")
})
}
shinyApp(ui, server)