住宅ローン計算機と調整可能な償却スケジュールを作成する目的で、最初の Shiny アプリを作成しています。次のコードを runApp() でレンダリングできますが、機能しません (つまり、値を出力せず、グラフも表示しません)。さらに、RStudio のコンソールで次のエラーが生成されます。
「.getReactiveEnvironment()$currentContext() のエラー: アクティブなリアクティブ コンテキストなしでは操作は許可されません。(リアクティブ式またはオブザーバー内からのみ実行できることを実行しようとしました。)」
バックグラウンドで実行しています: Win 7、64 ビット OS | R v3.1.1 | RStudio v0.98.944
ここで定義されている手順を実装しようとしましたが、うまくいきませんでした: Shiny Tutorial Error in R R Shiny - Numeric Input without Selectors
ui.R
library(shiny)
shinyUI(
pageWithSidebar(
headerPanel(
h1('Amoritization Simulator for Home Mortgages'),
windowTitle = "Amoritization Simulator"
),
sidebarPanel(
h3('Mortgage Information'),
h4('Purchase Price'),
p('Enter the total sale price of the home'),
textInput('price', "Sale Price ($USD)", value = ""),
h4('Percent Down Payment'),
p('Use the slider to select the percent of the purchase price you
intend to pay as a down payment at the time of purchase'),
sliderInput('per.down', "% Down Payment", value = 20, min = 0, max = 30, step = 1),
h4('Interest Rate (APR)'),
p('Use the slider to select the interest rate of the loan expressed
as an Annual Percentage Rate (APR)'),
sliderInput('apr', "APR", value = 4, min = 0, max = 8, step = 0.125),
h4('Term Length (Years)'),
p('Use the buttons to define the term of the loan'),
radioButtons('term', "Loan Term (Years)", choices = c(15, 30), selected = 30),
submitButton('Calculate')
),
mainPanel(
h3('Payment and Amoritization Simulation'),
p('Use this tool to determine your monthly mortgage payment,
how much interest you will owe over the life of the loan, and how
you can reduce that amount with additional payment'),
h4('Monthly Payment (Principal and Interest)'),
p('This is the amount (in $USD) you would pay each month for a
mortgage under the terms you defined'),
verbatimTextOutput("base.monthly.payment"),
h4('Total Interest Over Life of Loan'),
p('If paying just that amount per month, this is the total amount
in $USD you will spend on interest for that loan'),
verbatimTextOutput("base.total.interest"),
h4('Additional Principal Simulation'),
p('One way to reduce the interest expense is to pay more principal
each month. Use the slider below to select an additional amount to
include with your payment and see the reduction in interest expense
for the life of the loan.'),
sliderInput('add', "Additional Principal ($USD)", value = 250, min = 0, max = 1000, step = 25),
p('Interest costs saved with this additional principal (in $USD)'),
verbatimTextOutput("savings"),
p('You will also pay the loan off the loan this many months early'),
verbatimTextOutput("early"),
plotOutput('plot')
)
)
)
サーバー.R
library(shiny)
library(ggplot2)
library(scales)
shinyServer(
function(input, output) {
## determine baseline payment and interest total
price <- reactive({as.numeric(input$price)})
per.down <- reactive({input$per.down / 100})
int <- reactive({input$apr / 1200})
n <- reactive({input$term * 12})
base.monthly.payment <- (int() * price() * (1 - per.down()) * ((1 + int())^n())) / (((1 + int())^n()) - 1)
output$base.monthly.payment <- renderPrint({base.monthly.payment})
base.total.interest <- (base.monthly.payment * n()) - (price() * (1 - per.down()))
output$base.total.interest <- renderPrint({base.total.interest})
## create dataframe to populate with increments of additional payment
schedule <- data.frame(matrix(data = NA, nrow = 41, ncol = 6,
dimnames = list(1:41, c("add", "add.n",
"prin", "add.total.interest",
"savings", "early"))))
## initialize 'for' loop to populate possible amoritization totals
c <- 1
for (i in seq(0, 1000, 25)) {
schedule$add[c] <- i
schedule$add.n[c] <- log(((base.monthly.payment + i) / int()) / (((base.monthly.payment + i) / int()) - (price() * (1 - per.down())))) / log(1 + int())
schedule$prin[c] <- round(price() * (1 - per.down()), digits = 2)
schedule$add.total.interest[c] <- round(((base.monthly.payment + i) * schedule$add.n[c]) - schedule$prin[c], digits = 2)
schedule$savings[c] <- round(base.total.interest - schedule$add.total.interest[c], digits = 2)
schedule$early[c] <- round(n() - schedule$add.n[c], digits = 0)
c <- c + 1
}
add <- reactive({input$add})
output$savings <- renderPrint({schedule$savings[which(schedule$add == add())]})
output$early <- renderPrint({schedule$early[which(schedule$add == add())]})
## create data.frame suitable for plotting
graph.data <- data.frame(matrix(data = NA, nrow = 82, ncol = 3,
dimnames = list(1:82, c("add", "amount", "type"))))
c <- 1
for (i in seq(0, 1000, 25)) {
graph.data$add[c] <- i
graph.data$add[c + 1] <- i
graph.data$amount[c] <- schedule$prin[which(schedule$add == i)]
graph.data$amount[c + 1] <- schedule$add.total.interest[which(schedule$add == i)]
graph.data$type[c] <- "Principal"
graph.data$type[c + 1] <- "Interest"
c <- c + 2
}
## create plot of amoritization with line for additional principal amount
output$plot <- renderPlot({
ggplot(graph.data, aes(x = add, y = amount), color = type)
+ geom_area(aes(fill = type), position = 'stack', alpha = 0.75)
+ geom_vline(xintercept = add(), color="black", linetype = "longdash", size = 1)
+ labs(x = "Additional Principal/Month", y = "Total Cost")
+ scale_fill_manual(values=c("firebrick3", "dodgerblue3"), name = "Payment Component")
+ theme(axis.title.x = element_text(face = "bold", vjust = -0.7, size = 16),
axis.title.y = element_text(face = "bold", vjust = 2, size = 16),
axis.text.x = element_text(size = 14),
axis.text.y = element_text(size = 14),
panel.margin = unit(c(5, 5, 5, 5), "mm"),
plot.margin = unit(c(5, 5, 5, 5), "mm"),
panel.background = element_blank(),
panel.grid.major.y = element_line(colour = "gray"),
panel.grid.minor.y = element_line(colour = "gray86"),
panel.grid.major.x = element_blank(),
panel.grid.minor.x = element_blank())
+ scale_x_continuous(labels = dollar)
+ scale_y_continuous(labels = dollar)
})
})
助けてくれてありがとう！