我想知道为什么assign函数不能在reactValues内部工作？我需要将一个函数定义reactiveValues为向量中的所有元素（零）。这些元素是事先未知的，因为它们是最初打开的csv文件中所有变量的列名。因此，我不能简单地一一设置值。任何建议都将受到高度赞赏。
ui <- shinyUI(fluidPage(
titlePanel("Wondering"),
sidebarLayout(
sidebarPanel(
actionButton(inputId = "add_one", label = "", icon = icon("plus"))
),
mainPanel(
tabsetPanel(
tabPanel("Simple example",textOutput("test1"))
)
)
)
)
)
##########
# SERVER #
##########
server <- shinyServer(function(input, output) {
col_names <- c("A", "B")
# Assign zeros to all elements from col_names
# Please, use the assign function to do that!
rv <- reactiveValues(
# 1 How can I assign the initial value of zero to all column names?
# This is easy:
A = 0, B = 0
# But, in reality, in my app I do not know the variable names in advance, I just extract them and save
# in the col_names vector. Now, I need to assign initial value of zero to all column names
# I thought this might work, but no luck: All arguments passed to reactiveValues() must be named.
#for (k in 1:length(col_names)){
#
# assign(col_names[k], 0)
#}
)
# Sure, I will later have to figure out how to define observeEvent(s) for the unknown number of column names, but I am not there yet...
observeEvent(input$add_one, {
rv$A <- rv$A + 1
})
observeEvent(input$add_one, {
rv$B <- rv$B + 1
})
# Output text
output$test1 <-renderText({
paste(rv$A, rv$B)
})
})
shinyApp(ui = ui, server = server)
您可以这样做：
rv <- reactiveValues()
for(colname in col_names){
rv[[colname]] <- 0
}
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