如果bar的名称类别是字符，如何使用geom_bar连接堆叠的bar比例

编程问答 2022-06-08

问题描述

这是对here找到的问题的先前答案的扩展

简而言之，@Jon Spring使用以下示例代码来生成堆叠的条形图，其线连接两组之间的每个条形比例：

library(ggplot2)
set.seed(0)
data_bar <- data.frame(
  stringsAsFactors = F,Sample = rep(c("A","B"),each = 10),Percentage = runif(20),Taxon = rep(1:10,by = 2)
)
library(tidyr)
ggplot() +
  geom_bar(data = data_bar,aes(x = Sample,y =Percentage,fill = Taxon),colour = 'white',width = 0.3,stat="identity") +
  geom_segment(data = tidyr::spread(data_bar,Sample,Percentage),colour = "white",aes(x = 1 + 0.3/2,xend = 2 - 0.3/2,y = cumsum(A),yend = cumsum(B))) +
  theme(panel.background = element_rect(fill = "black"),# to make connecting points          
        panel.grid = element_blank())

geom_seg example

尽管这是一段精美的代码，可以解决连接柱形比例的问题，但是一旦柱形比例名称是字符串而不是上面的整数，我就无法以某种方式重现它。这是我的代码：

test.matrix<-matrix(c(70,120,65,140,13,68,46,294,52,410),ncol=2,byrow=TRUE)
rownames(test.matrix)<-c("BC.1","BC.2","GC","MO","EB")
colnames(test.matrix)<-c("12m","3m")
test.matrix <- data.frame(test.matrix)

ggplot() +
  geom_bar(data = test.matrix,aes(x = Var2,y =Freq,fill = Var1),colour = 'black',stat="identity") +
  geom_segment(data = tidyr::spread(test.matrix,Var2,Freq),colour = "black",y = cumsum(`12m`),yend = cumsum(`3m`))) +
  scale_fill_manual(values=c('BC.1'="gold",'BC.2'="yellowgreen",'GC'="navy",'MO'="royalblue",'EB'="orangered")) +
  theme(panel.background = element_rect(fill = "white"),panel.grid = element_blank())

geom_seg char

结果不匹配geom_segment线和钢筋比例。也许与cumsum()使用字符串的字母顺序有关，但是我无法弄清楚如何解决这个问题-或它完全不同...

所以我有两个问题：

  1. 如果必须确定比例顺序，如何连接钢筋比例？ （每个值组或每个行的字符串矢量或因子作为“名称”）

  2. 如何在每个条的最底部生成一个额外的geom_segment，以将每个条的两个下端彼此连接？

解决方法

  1. 问题在于您cumsum遇到了错误的“方向”或顺序，即，您在cumsum处BC.1定位，而条形图位于顶部。只需在累积之前重新排列数据集即可解决此问题。因此，我认为最好在绘图代码之外执行此操作，以便您可以轻松检查数据。

  2. 要在底部再添加一个geom_segment，您只需在数据中添加一行即可。

library(tidyverse)

test.matrix<-matrix(c(70,120,65,140,13,68,46,294,52,410),ncol=2,byrow=TRUE)
rownames(test.matrix)<-c("BC.1","BC.2","GC","MO","EB")
colnames(test.matrix)<-c("12m","3m")
test.matrix <- data.frame(test.matrix)

test.matrix <- test.matrix %>% 
  setNames(c("12m","3m")) %>% 
  rownames_to_column(var = "Var1") %>% 
  pivot_longer(-Var1,names_to = "Var2",values_to = "Freq")

test.matrix.wide <- tidyr::spread(test.matrix,Var2,Freq) %>% 
  arrange(desc(Var1)) %>% 
  mutate(y = cumsum(`12m`),yend = cumsum(`3m`)) %>% 
  add_row(y = 0,yend = 0)

ggplot() +
  geom_bar(data = test.matrix,aes(x = Var2,y =Freq,fill = Var1),colour = 'black',width = 0.3,stat="identity") +
  geom_segment(data = test.matrix.wide,colour = "black",aes(x = 1 + 0.3/2,xend = 2 - 0.3/2,y = y,yend = yend)) +
  scale_fill_manual(values=c('BC.1'="gold",'BC.2'="yellowgreen",'GC'="navy",'MO'="royalblue",'EB'="orangered")) +
  theme(panel.background = element_rect(fill = "white"),panel.grid = element_blank())

geom-barggplot2rrtidyr