如果 ggplot 中有 2 个图例，图例框颜色会发生变化答案

【问题标题】：legend box color changes if 2 legends in ggplot如果 ggplot 中有 2 个图例，图例框颜色会发生变化
【发布时间】：2021-08-20 11:53:51
【问题描述】：

我正在尝试根据以下df生成一个ggplot

df <- data.frame(
  Input = c("S1", "S2", "S3", "S4"),
  Brand = c("Brand01", "Brand01", "Brand01", "Brand01", "Brand02","Brand02","Brand02","Brand02"),
  Average = c(21.52027, 21.60699, 20.77871, 21.22759, 25.05574, 22.74372, 22.80795, 22.98509),
  Limit = c(31.89098, 31.89098, 31.89098, 31.89098, 31.57953, 31.57953, 31.57953, 31.57953))

p = ggplot(df, aes(x=Input, y=Average, fill=Brand)) +
       facet_wrap(~ Brand, ncol = 2) +
       geom_bar(stat="identity", position=position_dodge(), colour="black", width = 0.9, show.legend = FALSE) +
       xlab("Input") + ylab("Average") +
       theme(axis.title.x = element_text(size=14), axis.title.y = element_text(size=14),
             legend.text = element_text(size=14), plot.title = element_text(size = 20, face = "bold"),
             axis.text.x = element_text(size=6))+ 
       theme(axis.text.x = element_text(angle = 90)) +
       geom_hline(aes(yintercept=Limit, linetype = "dashed"), color = "red") +
       scale_linetype_manual(name = "Limit", values = "dashed", labels = "")

当show.legend = FALSE 时，情节看起来像但是当我有show.legend = TRUE 然后限制框改变颜色，我想让它像第一个情节一样“灰色”或白色。我尝试了其他相关主题的一些技巧，但没有任何效果。

【问题讨论】：

标签： r ggplot2 legend

【解决方案1】：

因为您在主 ggplot2 调用中声明了 fill = Brand，所以它被每一层继承。如果将其移动到geom_bar() 层，则图例应该会合理显示。

library(ggplot2)

df <- data.frame(
  Input = c("S1", "S2", "S3", "S4"),
  Brand = c("Brand01", "Brand01", "Brand01", "Brand01", "Brand02","Brand02","Brand02","Brand02"),
  Average = c(21.52027, 21.60699, 20.77871, 21.22759, 25.05574, 22.74372, 22.80795, 22.98509),
  Limit = c(31.89098, 31.89098, 31.89098, 31.89098, 31.57953, 31.57953, 31.57953, 31.57953))

ggplot(df, aes(x=Input, y=Average)) +
  facet_wrap(~ Brand, ncol = 2) +
  geom_bar(aes(fill=Brand), stat="identity", position=position_dodge(), colour="black", width = 0.9) +
  xlab("Input") + ylab("Average") +
  theme(axis.title.x = element_text(size=14), axis.title.y = element_text(size=14),
        legend.text = element_text(size=14), plot.title = element_text(size = 20, face = "bold"),
        axis.text.x = element_text(size=6))+ 
  theme(axis.text.x = element_text(angle = 90)) +
  geom_hline(aes(yintercept=Limit, linetype = "dashed"), color = "red") +
  scale_linetype_manual(name = "Limit", values = "dashed", labels = "")

^{由reprex package (v1.0.0) 于 2021-08-20 创建}

【讨论】：