如何在 ggplot2 的单个图形中绘制两条趋势线？

Question

我正在为具有两种处理和 3 个样本的基因表达数据绘制一条带有平滑趋势线的线图。 长格式的示例如下所示，

Group   Gene    Sample  exp
C   Gene_1  Sample1 0.8833248
C   Gene_2  Sample1 2.9193536
C   Gene_3  Sample1 -4.27416
S   Gene_1  Sample1 -1.6297201
S   Gene_2  Sample1 3.6535838
S   Gene_3  Sample1 -4.27416
C   Gene_1  Sample2 -0.3275709
C   Gene_2  Sample2 3.4885281
.
.
C   Gene_3  Sample3 -2.923909
S   Gene_1  Sample3 0.3514516
S   Gene_2  Sample3 2.981017
S   Gene_3  Sample3 -3.1599246

这里的问题是我可以为每种治疗分别制作趋势图，但我不知道如何在同一张图中绘制两种治疗的趋势线。 我做了类似的事情，

C_S<-ggplot(CS_long_fmt, aes(x=Sample, y=exp)) +
geom_line(aes(group=Gene)) +
stat_summary(aes(x=as.numeric(Sample)), fun=mean, geom='line',
           size=1, color='blue')

Answer 1

要为每个Group （治疗？）获得单独的趋势线，您必须将group美学添加到stat_summary 。

注意：另外，我在color aes 上映射以区分线条。

library(ggplot2)

ggplot(CS_long_fmt, aes(x = Sample, y = exp)) +
  geom_line(aes(group = Gene)) +
  stat_summary(aes(x = Sample, group = Group, color = Group),
    fun = mean, geom = "line",
    size = 1
  )

数据

CS_long_fmt <- structure(list(Group = c(
  "C", "C", "C", "S", "S", "S", "C", "C",
  "C", "S", "S", "S"
), Gene = c(
  "Gene_1", "Gene_2", "Gene_3", "Gene_1",
  "Gene_2", "Gene_3", "Gene_1", "Gene_2", "Gene_3", "Gene_1", "Gene_2",
  "Gene_3"
), Sample = c(
  "Sample1", "Sample1", "Sample1", "Sample1",
  "Sample1", "Sample1", "Sample2", "Sample2", "Sample3", "Sample3",
  "Sample3", "Sample3"
), exp = c(
  0.8833248, 2.9193536, -4.27416,
  -1.6297201, 3.6535838, -4.27416, -0.3275709, 3.4885281, -2.923909,
  0.3514516, 2.981017, -3.1599246
)), class = "data.frame", row.names = c(
  NA,
  -12L
))