R：ggplot彩色条形图按符号？ 绿色 = 正极，红色 = 负极

Question

I am looking to adjust my chart so that the returns below zero are in Red and the positive are green. I put a comment next to the two lines I have been messing around with (the problem is in the last set of lines of code. Everything else was working fine beforehand.

library(tidyverse)
library(tidyquant)
library(shiny)

#Stock assignments
stock_1<-'AMZN'
stock_2<-'CMG'
stock_3<-'TSS'  
stock_4<-'FB'
stock_5<-'T'

#Creating Input Boxes for Stocks and Weights of the Portfolio
ui <- fluidPage(
  titlePanel('Portfolio Daily Returns'),
  sidebarLayout(
    sidebarPanel(
      fluidRow(
        column(6,textInput("S1",h3('Input Stock 1'),stock_1)),
        column(6,numericInput("w1",h3("Input Weight 1"),.25))
      ),
      fluidRow(
        column(6,textInput("S2",h3('Input Stock 2'),stock_2)),
        column(6,numericInput("w2",h3("Input Weight 2"),.25))
      ),
      fluidRow(
        column(6,textInput("S3",h3('Input Stock 3'),stock_3)),
        column(6,numericInput("w3",h3("Input Weight 3"),.2))
      ),
      fluidRow(
        column(6,textInput("S4",h3('Input Stock 4'),stock_4)),
        column(6,numericInput("w4",h3("Input Weight 4"),.2))
      ),
      fluidRow(
        column(6,textInput("S5",h3('Input Stock 5'),stock_5)),
        column(6,numericInput("w5",h3("Input Weight 5"),.1))
      ),
      dateRangeInput("D",h3("Input Start and End Dates"),
                     '2019-09-01',Sys.Date())
    ),
    mainPanel(plotOutput("plot"))
  )
)
server <- function(input,output){
  dataInput <- reactive({
    tq_get(c(input$S1,input$S2,input$S3,input$S4,input$S5),from=input$D[1],to=input$D[2])%>%
      group_by(symbol)%>%
      tq_transmute(select=volume,mutate_fun = periodReturn,period='daily',
                   col_rename = 'Daily_Vol')%>%
      tq_portfolio(assets_col=symbol,returns_col = Daily_Vol,weights=c(
        input$w1,input$w2,input$w3,input$w4,input$w5),col_rename = 'Port_Vol')
  })

  dataInput[["sign"]] = ifelse(dataInput[["value"]] >= 0, "positive", "negative") #Problem
  output$plot <- renderPlot({
    ggplot(dataInput(),aes(x=date,y=Port_Vol))+geom_col()+
      scale_fill_manual(values = c("positive"="green","negative"=red)) #Problem 2
  })
}

shinyApp(ui=ui,server=server)```

Answer 1

Problem 1: dataInput is a reactive object. You should always call it out with dataInput(), and you cannot alter it. Either you mutate it while plotting or you simply add on to the data.frame before returning. So I added the positive /negative inside the dataInput call

Problem 2: you need to quote "red". Also you need to specify fill=sign in the aes

Below I have edited your server function, it should work, there is some warning messages about NA, and I am not so familiar with the zoo functions, so I leave you to sort it out

server <- function(input,output){
  dataInput <- reactive({
    dat <- tq_get(c(input$S1,input$S2,input$S3,input$S4,input$S5),from=input$D[1],to=input$D[2])%>%
      group_by(symbol)%>%
      tq_transmute(select=volume,mutate_fun = periodReturn,period='daily',
                   col_rename = 'Daily_Vol')%>%
      tq_portfolio(assets_col=symbol,returns_col = Daily_Vol,weights=c(
        input$w1,input$w2,input$w3,input$w4,input$w5),col_rename = 'Port_Vol')
    dat$sign = ifelse(dat$Port_Vol >= 0, "positive", "negative")
    return(dat)
  })

  output$plot <- renderPlot({
    ggplot(dataInput(),aes(x=date,y=Port_Vol,fill=sign))+geom_col()+
      scale_fill_manual(values = c("positive"="green","negative"="red")) #Problem 2
  })
}