[英]How do I get a summary table from a custom function to react to user input of variables?
這是我第一次嘗試使用 Shiny。
我有一個帶有 4 個變量的模擬患者級數據集:
嘗試構建一個簡單的應用程序,它接受兩個輸入:星期和變量,並提供兩個輸出:
我能夠創建交互式箱線圖,但無法創建匯總表。 我能夠使用來自 doBy 的 summaryBy 函數在 RMarkdown 中創建此表的靜態版本,但我無法在 Shiny 中實現它。 嘗試遵循此處和此處的建議,但我遺漏了一些東西。
這是我的可重復性代碼。 原諒大量的注釋,(我是一個完整的初學者)它們更適合我自己而不是其他任何人。
#libraries--------------------
library(shiny)
library(tidyverse)
library(knitr)
library(doBy)
#----------------------------
#input data
set.seed(123)
mydf <- data.frame( group = rep(rep(c("A","B","C"), each = 3), times = 3),
week = rep(rep(c(1,4,8), each = 9)),
painscore = sample(1:10, 27, replace = TRUE),
dependscore = sample(1:10, 27, replace = TRUE) )
#--------------------------
#define custom function to calculate summary statistics for column of interest.
#function explained in a little more detail when applied in the server function.
fun <- function(x) {
c( n = length(x),
m = median(x),
firstq = round(quantile(x)[2], 1),
lastq = round(quantile(x)[4], 1),
missing = mean(is.na(x)))
}
#-------------------------
#UI
ui <- fluidPage(
titlePanel("Shiny Boxplot and Table"),
#User can provide two different inputs
sidebarLayout(
sidebarPanel(
#1. allow user to pick week using radiobuttons
radioButtons(inputId = "pickedwk",
label = "week you want to display",
choices = c(1,4,8),
selected = 1),
#2. user can pick variable to visualize using dropdownboxes
selectInput(inputId = "var",
label = "variable to visualize",
list("How much pain did you feel today?" = "painscore",
"How dependent are you on medication?" = "dependscore")),
#helpertext
helpText("Enter week/variable choices here")
),
#Spaceholders for output
mainPanel(
plotOutput("boxplot"), #boxplot placeholder
htmlOutput("descriptives") #kable html table placeholder
)
)
)
#-------------------------
#Server
server <- function(input, output) {
#create dataset that subsets down to the week picked by user.
weeksub <- reactive({
mydf %>% filter(week == input$pickedwk[1])
})
#1. use reactive datasubset to render boxplot.
output$boxplot <- renderPlot({
ggplot(weeksub(), aes_string(x = "group", y = input$var)) + #input$var works here
geom_boxplot(fill = "red", outlier.shape = 15, outlier.color = "black") +
scale_y_continuous(name = as.character(input$var)) +
scale_x_discrete(name = "group") +
ggtitle(paste("Distribution of", as.character(input$var), "by treatment group"))
})
#2. use same reactive datasubset to render kable descriptive statistics for the variable picked.
output$descriptives <- renderText({
kable(summaryBy(input$var ~ group, data = as.data.frame(weeksub()), FUN = fun),
#note: here, I'm using the summaryBy function from package doBy. It takes the form var~ categoricalvar
# so, either painscore ~ group, or dependscore ~ group depending on what the user picked, and uses
#my custom function to return a table of count, median, 25th percentile, 75th percentile and missing count for
#the 3 levels of the group variable (for A, B, and C)
col.names = c("Number", "Median", "1Q", "3Q", "Missing"))
})
}#server function ends
# Run the application
shinyApp(ui = ui, server = server)
您的代碼中有幾個問題:
input$var
。 summaryBy
支持一種效果更好的替代語法。 (您也可以使用as.formula
和paste
來構建公式。)col.names
的“組”列kable
生成 HTML 並將其作為 HTML 傳遞給 UI。將您的表輸出更改為:
output$descriptives <- renderUI({
HTML(kable(summaryBy(list(input$var, 'group'), data = as.data.frame(weeksub()), FUN = fun),
col.names = c('Group', "Number", "Median", "1Q", "3Q", "Missing"),
format='html'
))
})
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