我查遍了互联网并尝试了多种解决方案，但似乎都不起作用。 简而言之，这是我的问题:我创建了一个 Shiny 的应用程序，用户可以在其中上传 csv 文件并将它们保存在数据集中。现在我想将每个上传的数据集保存在一个列表中，这将帮助我通过 selectInput 按钮选择要查看的数据集这是我到目前为止编写的代码:
server <- function(input, output) {
datasetlist <- list()
output$contents <- renderTable({
# input$file1 will be NULL initially. After the user selects
# and uploads a file, head of that data file by default,
# or all rows if selected, will be shown.
req(input$file1)
input$update
tryCatch({
df <- read.csv(
input$file1$datapath,
header = isolate(input$header),
sep = isolate(input$sep),
dec = isolate(input$dec),
quote = isolate(input$quote)
)
},
error = function(e) {
# return a safeError if a parsing error occurs
stop(safeError(e))
})
# when reading semicolon separated files,
# having a comma separator causes `read.csv` to error
if (isolate(input$disp == "head")) {
return(head(df))
}
else {
return(df)
}
})
output$manage <- renderUI({
selectInput("dataset", "Dataset", choices = datasetlist[], selected = datasetlist[1])
})
}
奖励点:如果有人也指出如何从列表中删除记录而不影响整个列表，我会很高兴
编辑1:按照我之前收到的答案，现在是完整的代码，问题是我似乎找不到显示数据集表格的方法
#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#
# Find out more about building applications with Shiny here:
#
# http://shiny.rstudio.com/
#
library(shiny)
library(shinydashboard)
library(shinythemes)
library(shinyFiles)
options(shiny.maxRequestSize = 30 * 1024 ^ 2)
# Define UI for application
ui <- fluidPage(#theme= shinytheme("paper"),
# Application title
navbarPage(
"Title",
# Sidebar with input
tabPanel("Data Manager",
sidebarLayout(
sidebarPanel(
uiOutput("manage"),
fileInput(
"file1",
"Choose CSV File",
multiple = FALSE,
accept = c("text/csv",
"text/comma-separated-values,text/plain",
".csv")
),
# Horizontal line ----
tags$hr(),
fluidRow(
# Input: Checkbox if file has header ----
column(4 ,checkboxInput("header", "Header", TRUE)),
# Input: Select number of rows to display ----
column(8, radioButtons(
"disp",
"Display",
choices = c(Head = "head",
All = "all"),
selected = "head",
inline = TRUE
))),
fluidRow(# Input: Select separator ----
column(
4, selectInput(
"sep",
"Separator",
choices = c(
Comma = ",",
Semicolon = ";",
Tab = "\t"
),
selected = ";"
)
),
# Input: Select decimals ----
column(
4 , selectInput(
"dec",
"Decimal",
choices = c("Comma" = ",",
"Period" = '.'),
selected = ','
)
)),
# Input: Select quotes ----
fluidRow(column(8 , selectInput(
"quote",
"Quote",
choices = c(
None = "",
"Double Quote" = '"',
"Single Quote" = "'"
),
selected = '"'
))),
# Horizontal line ----
tags$hr(),
actionButton("update", "Update")
),
mainPanel(fluidRow(tableOutput("contents")))
))
))
# Define server logic
server <- function(input, output, session) {
rv <- reactiveValues(
datasetlist = list()
)
observe({
# input$file1 will be NULL initially. After the user selects
# and uploads a file, head of that data file by default,
# or all rows if selected, will be shown.
req(input$file1)
input$update
tryCatch({
df <- read.csv(
input$file1$datapath,
header = isolate(input$header),
sep = isolate(input$sep),
dec = isolate(input$dec),
quote = isolate(input$quote)
)
},
error = function(e) {
# return a safeError if a parsing error occurs
stop(safeError(e))
})
# when reading semicolon separated files,
# having a comma separator causes `read.csv` to error
isolate(
rv$datasetlist <- c(rv$datasetlist,list(df))
)
})
observe({
updateSelectInput(
session = session,
inputId = "selected_dataset",
choices = 1:length(rv$datasetlist),
selected = input$selected_dataset
)
})
output$contents <- renderTable({
req(length(rv$datasetlist) >= input$selected_dataset)
df <- rv$datasetlist[[input$selected_dataset]]
if (isolate(input$disp == "head")) {
return(head(df))
}
else {
return(df)
}
})
output$manage <- renderUI({
tagList(
selectInput("selected_dataset", "Dataset", choices = '', selected = 1)
)
})
}
# Run the application
shinyApp(ui = ui, server = server)
最佳答案
使用 file.copy() 将用户上传的文件复制到 Selected_Files 文件夹中，然后使用 eventReactive() 将文件夹中的所有文件读取到列表说数据集列表。将数据集列表的元素命名为文件名。您可以使用 datasetlist() 在 renderUI/renderTable 中使用此列表响应式(Reactive)上下文。
我编写了下面的代码，它可能会解决您的目的。进一步注意 read.csv 有 sep 参数，它负责处理不同的分隔符。我使用单选按钮为用户提供文件分隔符。
编辑:为了正确捕获所有上传文件的文件格式，我创建了一个列表df，捕获用户输入文件格式并将其保存为 R 对象File_Format.rds 在工作目录中。然后使用 readRDS 将保存的列表加载为 old_df 并将其附加到当前 df。
Edit2:我发现，当使用不同参数上传同一文件时，列表File_Format的名称保持相同，因此重复的第一个元素被选中。我通过将上传计数作为名称的索引作为前缀解决了这个问题。此外，在代码的开头，我添加了两条语句来删除 RDS 文件以及 Selected_Files 文件夹中的所有文件。因此，每当打开应用程序时，这些文件都会首先被删除，然后才是交互式 session 。
更新后的代码如下
library(shiny)
if (file.exists("File_Format.rds")) file.remove("File_Format.rds")
do.call(file.remove, list(list.files("Selected_Files", full.names = TRUE)))
ui <- fluidPage(
# tableOutput("contents"),
sidebarPanel(
fileInput("file1", "Choose CSV File",
multiple = FALSE,
accept = c("text/csv",
"text/comma-separated-values,text/plain",
".csv")),
# Horizontal line ----
tags$hr(),
# Input: Checkbox if file has header ----
checkboxInput("header", "Header", TRUE),
# Input: Select separator ----
radioButtons("sep", "Separator",
choices = c(Comma = ",",
Semicolon = ";",
Tab = "\t"),
selected = ","),
# Input: Select quotes ----
radioButtons("quote", "Quote",
choices = c(None = "",
"Double Quote" = '"',
"Single Quote" = "'"),
selected = '"'),
# Horizontal line ----
tags$hr(),
# Upload Button
actionButton("uploadId", "Upload")
),
# Main panel for displaying outputs ----
mainPanel(
# # Output: Data file ----
uiOutput("manage"),
# Input: Select number of rows to display ----
uiOutput("select"),
# Display Button
actionButton("displayid", "Display"),
tableOutput("contents")
)
)
########### Server ###########
server <- function(input, output, session) {
# Copy uploaded files to local folder
observeEvent(input$uploadId,{
if (is.null(input$file1) ) { return(NULL) }
file.copy(from = input$file1$datapath, to = paste0('Selected_Files/',input$file1$name ) )
df <- list(file = input$file1$name , header= input$header,
sep = input$sep,dec = input$dec,
quote = input$quote,
index = input$uploadId)
if(input$uploadId > 1){
old_df <- readRDS("File_Format.rds")
df <- sapply(names(old_df),function(n){c(old_df[[n]],df[[n]])},simplify=FALSE)
}
saveRDS(df, "File_Format.rds")
})
# Load all the uplaoded files to a list
datasetlist <- eventReactive(input$uploadId,{
# Selected_Files <- list.files("Selected_Files/")
File_Format <- readRDS("File_Format.rds")
datalist <- list()
datalist <- lapply(1:length(File_Format[[1]]), function(d) read.csv(paste0("Selected_Files/",File_Format$file[d] ),
header = File_Format$header[d],
sep = File_Format$sep[d],
dec = File_Format$dec[d],
quote = File_Format$quote[d]))
names(datalist) <- paste(File_Format$index, File_Format$file,sep = ". ")
return(datalist)
})
output$manage <- renderUI({
data <- datasetlist()
selectInput("dataset", "Dataset", choices = names(data), selected = names(data))
})
output$select <- renderUI({
data <- datasetlist()
radioButtons("disp", "Display", choices = c(Head = "head",All = "all"),
selected = "head")
})
# Display Selected File
observeEvent(input$displayid, {
output$contents <- renderTable({
data <- datasetlist()
sub_df <- data[[paste0(input$dataset)]]
if (isolate(input$disp == "head")) {
return(head(sub_df))
}
else {
return(sub_df)
}
})
})
}
shinyApp(ui, server)
希望这对您有所帮助。
关于R + Shiny : Save Uploaded Dataset to List/choose from list item to view，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/52074498/