r - 在绘制多条线时调整组美学？

Question

在执行以下 Shiny 代码时：

library("shiny")
library("ggplot2")
library("DT")
library("reshape2")
## load data ##

aqi = read.csv(file = "C:/Users/stan/Desktop/AIR/month.csv",
               header = T, sep = ",")
str(aqi)
colnames(aqi) = c("num","month", 
                  "PM10","PM2.5","NO","NO2")
## ui.R ##

ui = fluidPage(
  titlePanel('AIR'),
  sidebarLayout(
    sidebarPanel(
      selectInput('month',
                  'Choose a month:',
                  c('All', unique(as.character(aqi$month)
                  ))),
      selectInput('PM10',
                  'Number of :PM10',
                  c('All', unique(as.character(aqi$PM10)
                  ))),
      selectInput('PM2.5',
                  'Number of PM2.5:',
                  c('All',unique(as.character(aqi$PM2.5)
                  ))),
      selectizeInput("AIR", 
                     "Select Contaminant:", 
                     choices = c( "PM2.5", 
                                  "PM10"), 
                     selected = "PM2..5", 
                     multiple = TRUE )
  ),

    mainPanel(
      dataTableOutput('table'),
      plotOutput("plot")
    )
  )
)


## server.R ##

server = function(input, output) {
  # Filter data based on selections
  output$table <- DT::renderDataTable(DT::datatable({
    data <- aqi
    if (input$month != "All") {
      data <- data[aqi$month == input$month,]
    }
    if (input$PM10 != "All") {
      data <- data[aqi$PM10 == input$PM10,]
    }
    data
    if (input$PM2.5 != "All") {
      data <- data[aqi$PM2.5 == input$PM2.5,]
    }
    data
  }))
  output$plot = renderPlot({ 
    plot.data <- melt(aqi, id.vars= "month") 
    #not sure if input$cnt is a list or a vector 
    #may need to manipulate that before passing 
    plot.data <- plot.data[plot.data$variable %in% input$AIR, ] 
    ggplot(plot.data) + 
      geom_line(mapping = aes(x = month, y = value , colour =variable)) + 
      labs (x = "month", y = "value", title = "AIR") + 
      scale_colour_discrete(name = "AIR") 
  }) 
}

shinyApp(ui, server)

错误被抛出：

geom_path：每组仅包含一个观察值。需要调整群体审美吗？geom_path：每组仅包含一个观察值。需要调整群体审美吗？

我应该在美学上调整分组以避免上述错误吗？

这是我的数据：

1   num month   PM 10   PM 2.5  NO  NO2
2   1   1月  24  10  2.59    8.61
3   2   2月  45  20  2.14    9.94
4   3   3月  40  20  2.97    10.94
5   4   4月  51  20  2.16    11.27
6   5   5月  36  16  1.91    10.3
7   6   6月  33  13  1.89    8.85
8   7   7月  26  11  1.87    6.43
9   8   8月  28  13  2   9.4
10  9   9月  32  15  1.45    7.01
11  10  10月 35  15  1.26    7.77
12  11  11月 24  12  1.66    7.65
13  12  12月 21  11  2.06    8.22

Answer 1

您可以解决添加group = 1到美学中的问题，但是由于几个月的日文 unicode 字符转换为factor类型，结果在美学上并不令人愉悦。

另一种方法是使用连续缩放，同时使用从 1 到 12 的月份的数字绘制线条，然后手动添加标签和中断 - scale_x_continuous(breaks = 1:12, labels = month_label)。

请看下面的代码：

aqi <- structure(list(num = 1:12, month = structure(c(1L, 5L, 6L, 7L, 
8L, 9L, 10L, 11L, 12L, 2L, 3L, 4L), .Label = c("1<U+6708>", "10<U+6708>", 
"11<U+6708>", "12<U+6708>", "2<U+6708>", "3<U+6708>", "4<U+6708>", 
"5<U+6708>", "6<U+6708>", "7<U+6708>", "8<U+6708>", "9<U+6708>"
), class = "factor"), PM10 = c(24L, 45L, 40L, 51L, 36L, 33L, 
26L, 28L, 32L, 35L, 24L, 21L), PM2.5 = c(10L, 20L, 20L, 20L, 
16L, 13L, 11L, 13L, 15L, 15L, 12L, 11L), NO = c(2.59, 2.14, 2.97, 
2.16, 1.91, 1.89, 1.87, 2, 1.45, 1.26, 1.66, 2.06), NO2 = c(8.61, 
9.94, 10.94, 11.27, 10.3, 8.85, 6.43, 9.4, 7.01, 7.77, 7.65, 
8.22)), row.names = c(NA, -12L), class = "data.frame")


aqi$num <- NULL

library(ggplot2)
library(reshape2)
month_label <- aqi$month
aqi$month <- 1:nrow(aqi)

plot.data <- melt(aqi, id.vars= "month") 


ggplot(plot.data) + 
  geom_line(mapping = aes(x = month, y = value , colour = variable)) + 
  labs (x = "month", y = "value", title = "AIR") +
  scale_x_continuous(breaks = 1:12, labels = month_label)

输出：