曲线`geom_line（）`使用群体美学

Question

我有一个“网格”结构的数据，我希望根据组变量将某些点连接在一起。 geom_line()可以实现这一点（见下文），但我想让这些线条弯曲。怎么可以这样做？ geom_curve()似乎与此特定数据格式不兼容。谢谢。

df = data.frame(
 x = factor(c(1,1,2,2)),
 y = factor(c(1,2,1,2)),
 group = c("A","A","B","B")) 

df %>% 
 ggplot(aes(x = x, y = y)) +
 geom_point() +
 geom_line(aes(group = group))

Answer 1

# A "toy" data set    
df1 = data.frame(
 x = factor(c(1,1,2,2,3,3)),
 y = factor(c(1,2,1,2,1,2)),
 group = c("A","A","B","B","C","C")) 

library(ggplot2)
library(dplyr)

# Create a matrix where on each row there are the coordinates 
# of the starting and ending points
# One row for each group 
df1 %>% group_by(group) %>%
mutate(X1=x[1], X2=x[1], Y1=y[1], Y2=y[2]) -> df2
( df2 <- df2[seq(1,nrow(df2),2),c("X1","X2","Y1","Y2")] )
# A tibble: 3 x 4
#      X1     X2     Y1     Y2
#  <fctr> <fctr> <fctr> <fctr>
# 1      1      1      1      2
# 2      2      2      1      2
# 3      3      3      1      2

ggplot() +
 geom_point(data=df1, aes(x=x, y=y)) +
 geom_curve(data=df2,aes(x=X1, y=Y1, xend=X2, yend=Y2), curvature=.5)