在ggplot上添加百分比之间的百分比变化

Question

我有一个geom_bar图，其中包含视觉本身每个条形图的值。

以下是生成情节的代码：

# 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")})
  })

这是一个可以输入的数据框。

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"
))

以下是该情节的截图：

我想在每个条形图之间添加一个新行（可能是一个新的统计摘要？），显示百分比变化。对于前2个柱，会话和添加到购物车，值已从1.4M变为385k =下降~72％。所以，我想在条形图之间显示“72％”。

这样做有直接的方法吗？

我可以创建一个表并在可视化下显示它，但我想看看它如何将百分比下降添加到视觉本身。

如何在从左到右阅读的每个栏之间添加百分比下降？

Answer 1

您可以尝试：

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)