图例不遵循R中的有序条

Question

我的情节有两个问题：

（1）组栏的排列顺序不符合我的要求-我希望它们按输入的顺序显示，（2）图例，顺序显示为 V，E，B < / strong>，而在组中则显示为 B，E，V 。我可以改变传说，但是，我真正想要得到的是将子图的顺序更改为 V，E，B 。

library(ggplot2)

df2 <- data.frame(supp = rep(c("V","E","B"), each=5),
                  s = rep(c("C3","C1", "C2","C5","C6"), 3),
                  len = c(1,2,3,4,5,6,8,4,4,3,9,7,6,8,5))

p <- ggplot(data = df2, aes(x = s, y = len, fill = supp)) + 
       geom_bar(stat = "identity", color = "black", position = position_dodge())

p + scale_fill_brewer(palette = "Blues", guide = guide_legend(reverse = TRUE)) +
      scale_x_discrete(limits = rev(levels(df2$s))) 

Answer 1

您需要将df2$supp从字符更改为因数，并根据需要显示它们来指定级别。

请参阅下面的修改后的代码。另外，请查看this link，以获取有关如何控制变量颜色以使其一致的更多详细信息。

library(ggplot2)

df2 <- data.frame(supp = rep(c("V","E","B"), each=5),
                  s = rep(c("C3","C1", "C2","C5","C6"), 3),
                  len = c(1,2,3,4,5,6,8,4,4,3,9,7,6,8,5))

df2$supp <- factor(df2$supp,
                   levels = c("V", "E", "B"))

p <- ggplot(data=df2, aes(x=(df2$s), y=len, fill=supp)) + 
  geom_bar(stat="identity", color="black", position=position_dodge())

p + scale_fill_brewer(palette="Blues", guide = guide_legend(reverse=TRUE)) +
  scale_x_discrete(limits = rev(levels(df2$s))) 

Answer 2

数据

df2 <- data.frame(supp = rep(c("V", "E", "B"), each = 5),
                  s = rep(c("C3", "C1", "C2", "C5", "C6"), 3),
                  len = c(1, 2, 3, 4, 5, 6, 8, 4, 4, 3, 9, 7, 6, 8, 5))

调整

由于使用data.frame()创建数据，因此R默认情况下会将字符串设置为因子。因此，您需要将变量类型修改为所需的变量。

df2$s <- as.character(df2$s)
df2$supp <- factor(df2$supp, levels = c("V", "E", "B"))

情节

ggplot(data = df2, aes(x = s, y = len, fill = supp)) + 
  geom_bar(stat = "identity", color = "black", position = position_dodge()) +
  scale_fill_brewer(palette = "Blues", direction = -1)

在这里，你不需要使用额外的guide_legend()和scale_x_discrete()改变顺序。会更加简洁。