用正值和负值控制 ggplot::geom_bar position_stack 图形和图例中的填充颜色顺序

Question

我有一个包含三列的df：

-"sample" ~包含样本名称 -“组”~包含组（第一个向上，第二个向上，保持向上，保持向下，第二个向下，第一个向下） -"value" ~包含每组中的数字。

我在sorder 中按我想要的顺序订购的样本，并作为因子在 x 轴上对刻度进行排序。 以类似的方式，我对gorder 中的组进行了排序，并将它们作为因子应用于图中的堆栈排序。

我对图例中组的顺序（及其颜色）感到满意，并希望堆栈的顺序相同。我尝试重新排序因子，但由于没有手动挑选颜色，我没有设法按照与图例相同的顺序获得堆栈。你有什么建议吗？

require(dplyr)
require(ggplot2)

gorder<-c("first up", "second up", "remain up", "remain down", "second down", "first down")

sorder<-c("55_NST", "40_NST","25_NST","ad_NST", "RH_NST", "FT_ST",  "55_ST", "25_ST")

set.seed(1)
df<-data.frame(
  "sample" =rep(sorder, each=6),
  "group"=rep(gorder, times=8),
  "value"=c(abs(rnorm(48,mean=3000, sd=500))))
df<-df%>%mutate(value =case_when(group %in% c("remain down", "second down", "first down") ~ value *(-1),
                                 !group %in% c("remain down", "second down", "first down") ~ value))


df$sample<-factor(df$sample, levels = sorder)
df$group<-factor(df$group, levels = gorder)

ggplot(df, aes(fill=group, y=value, x=sample)) + 
    geom_bar(position="stack", stat="identity") +
 theme_bw()+
  scale_x_discrete(breaks=sorder, labels=c("55", "40", "25", "AD", "RH", "FT (ST)", "55 (ST)", "25 (ST)"))+
  scale_y_continuous(breaks = seq(from = -12000,to = 12000, by = 2000))+
  labs(y="number of genes", x="RWC")+
  scale_fill_brewer(type = "div", palette = "RdYlGn",direction = -1)

Example graph, I would like the stacks in the same order as the legend colors

Answer 1

困难似乎在于使用因子和 ggplot 处理position_stack 中的负值的方式之间的冲突。

来自文档：“正值和负值的堆叠是分开执行的，因此正值从 x 轴向上堆叠，负值向下堆叠。”似乎堆叠胜过因素。

所以需要一点人工干预：

1) 重新排序gorder 以处理负值的堆叠反转

2) 使用scale_fill_manual 和colorBrewer 调色板的重构版本以正确顺序在图表中获取填充颜色。按要求的顺序添加标签。

3) 覆盖图例指南，使颜色与原始标签顺序匹配。

可能有更有效的方法来实现这一点......

library(ggplot2)
library(dplyr)
library(forcats)
library(RColorBrewer)

gorder<-c("first up", "second up", "remain up", "remain down", "second down", "first down")

gorder_col <- c("first up", "second up", "remain up", rev(c("remain down", "second down", "first down")))

sorder<-c("55_NST", "40_NST","25_NST","ad_NST", "RH_NST", "FT_ST",  "55_ST", "25_ST")

set.seed(1)

df<-data.frame(
  "sample" = rep(sorder, each=6),
  "group" = rep(gorder, times=8),
  "value" = c(abs(rnorm(48,mean=3000, sd=500))))

df<-
  df %>%
  mutate(value = case_when(group %in% c("remain down", "second down", "first down") ~ value * (-1),
                           !group %in% c("remain down", "second down", "first down") ~ value),
         sample = factor(sample, levels = sorder),
         group = factor(group, levels = gorder_col))


ggplot(df, aes(fill = group, y = value, x = sample)) + 
  geom_bar(position="stack", stat="identity") +
  theme_bw()+
  scale_x_discrete(breaks = sorder, labels = c("55", "40", "25", "AD", "RH", "FT (ST)", "55 (ST)", "25 (ST)"))+
  scale_y_continuous(breaks = seq(from = -12000,to = 12000, by = 2000))+
  labs(y="number of genes", x="RWC")+
  scale_fill_manual(values = c(brewer.pal(name = "RdYlGn", n = 6)[6:4], brewer.pal(name = "RdYlGn", n = 6)[1:3]),
                    labels = gorder)+
  guides(fill = guide_legend(override.aes = list(fill = brewer.pal(name = "RdYlGn", n = 6)[6:1])))