在ggplot上的条之间添加百分比变化

Question

我有一个带有标签的geom_bar图，用于视觉上每个条的值。

这是生成绘图的代码：

# libraries
library(shiny)
library(tidyverse)

# funnel bar blot
  output$funnel_plot <- renderPlot({
    ggplot(exampledf, aes(x = reorder(Funnel, -Sessions), y = Sessions)) +
      geom_bar(stat = "identity", fill = "#008080", alpha = 0.6) +
      stat_summary(aes(label = scales::comma(..y..)), fun.y = 'sum', geom = 'text', col = 'white', vjust = 1.5) +
      xlab("Step") +
      ylab("Events") +
      scale_y_continuous(labels = function(l) {l = l / 1000; paste0(l, "K")})
  })

这是一个要馈入其中的数据帧。

exampledf <- structure(list(Channel = c("Facebook", "Youtube", "SEM", "Organic", 
"Direct", "Email", "Facebook", "Youtube", "SEM", "Organic", "Direct", 
"Email", "Facebook", "Youtube", "SEM", "Organic", "Direct", "Email", 
"Facebook", "Youtube", "SEM", "Organic", "Direct", "Email"), 
    Promo = c("None", "None", "None", "None", "None", "None", 
    "Partner Offer", "Partner Offer", "Partner Offer", "Partner Offer", 
    "Partner Offer", "Partner Offer", "Print Code", "Print Code", 
    "Print Code", "Print Code", "Print Code", "Print Code", "Affiliate Promo", 
    "Affiliate Promo", "Affiliate Promo", "Affiliate Promo", 
    "Affiliate Promo", "Affiliate Promo"), Sessions = c(26126, 
    16885, 32229, 2446, 16353, 79202, 7688, 83475, 48834, 53475, 
    71238, 78728, 76710, 125571, 125719, 17142, 103206, 181082, 
    27071, 42571, 716, 139871, 21676, 59560), AddToCart = c(7228, 
    4436, 8344, 575, 4275, 23681, 1982, 18489, 14433, 14995, 
    20769, 20119, 18471, 35566, 33423, 5187, 28138, 48186, 7140, 
    11602, 190, 35795, 5193, 17064), Registrations = c(2780, 
    1706, 3209, 221, 1644, 9108, 762, 7111, 5551, 5767, 7988, 
    7738, 7104, 13679, 12855, 1995, 10822, 18533, 2746, 4462, 
    73, 13767, 1997, 6563), ShippingDetails = c(1069, 656, 1234, 
    85, 632, 3503, 293, 2735, 2135, 2218, 3072, 2976, 2732, 5261, 
    4944, 767, 4162, 7128, 1056, 1716, 28, 5295, 768, 2524), 
    Checkout = c(668, 410, 771, 53, 395, 2189, 183, 1709, 1334, 
    1386, 1920, 1860, 1707, 3288, 3090, 479, 2601, 4455, 660, 
    1072, 17, 3309, 480, 1577), Transactions = c(556, 341, 642, 
    44, 329, 1824, 152, 1424, 1111, 1155, 1600, 1550, 1422, 2740, 
    2575, 399, 2167, 3712, 550, 893, 14, 2757, 400, 1314)), class = "data.frame", row.names = c(NA, 
-24L), .Names = c("Channel", "Promo", "Sessions", "AddToCart", 
"Registrations", "ShippingDetails", "Checkout", "Transactions"
))

这是该图的外观的屏幕截图：

我想在显示百分比变化的每个条之间添加新行（也许是新的统计摘要？）。对于前2个小节，会话和添加到购物车，值已从1.4M更改为385k =下降了〜72％。因此，我希望“ 72％”显示在条之间。

有直接的方法吗？

我可以只创建一个表格并在可视化效果下显示它，但我想看看它如何将百分比下降添加到视觉效果本身。

如何在从左至右的每个条形读数之间添加百分比下降？

Answer 1

你可以试试：

as.tbl(df) %>% 
  gather(key, value, -Channel, -Promo) %>% 
  group_by(key) %>% 
  summarise(Sum=sum(value)) %>% 
  arrange(-Sum) %>% 
  mutate(End=lag(Sum),
         xpos=1:n()-0.5,
         Diff=End-Sum,
         Percent=paste(round(Diff/End*100,1),"%")) %>% 
    ggplot(aes(x = reorder(key, -Sum), y = Sum)) +
    geom_col(alpha = 0.6) + 
    stat_summary(aes(label = scales::comma(..y..)), fun.y = 'sum', 
                 geom = 'text', col = 'white', vjust = 1.5) +
    geom_segment(aes(x=xpos, y = End, xend=xpos, yend=Sum)) +
    geom_text(aes(x=xpos,y =  End-Diff/2, label=Percent),hjust=-0.2)