ggplot线段从一个点到不同数据帧的多个点

Question

我有一个df，其起点是2个组，另一个是终点，是相同的组。我想绘制从第1组开始到满足条件的所有第1组末端，以及从第2组开始到满足条件的所有第2组末端的ggplot画线，但是我不知道我需要什么geom_用于实现这一目标，例如是否可以按照我的尝试从两个不同的数据帧中实现。

 # start coordinates:
 set.seed(5)
 start <- data.frame(matrix(nrow=2,ncol=3))
 colnames(start) <- c("group","X","Y")
 start$group <- c(1,2)
 start$X <- c(5,10)
 start$Y <- c(5,10)

 # end coordinates:
 df <- data.frame(matrix(nrow = 20,ncol=4))
 colnames(df) <- c("group","X","Y","condition")
 df$group <- rep(c(1,2),each=10)
 df$X <- runif(20,0,20)
 df$Y <- runif(20,0,20)
 df$condition <- c("n","n","n","y","n",
                   "y","n","n","y","y",
                   "y","n","n","y","n",
                   "y","y","y","n","y")

 # plot data
 library(ggplot2)
 ggplot(data=df,aes(x=X,y=Y,color=group))+
      geom_point(aes(shape=condition))+
      geom_point(data=start,aes(x=X,y=Y),size=2)

我想要的是每组从起点到“ condition = yes”终点的所有行。该图看起来像是两个重叠的星星，但是我无法弄清楚如何在一个geom_命令中从两个数据框调用。这是我到目前为止尝试过的。

 ggplot(data=df,aes(x=X,y=Y,color=group))+
 geom_point(aes(shape=condition))+
 geom_point(data=start,aes(x=X,y=Y),size=2)+  
 geom_segment(aes(x=start$X,
                  y=start$Y,
                  xend=df$X[df$condition=="y"],
                  yend=df$Y[df$condition=="y"],
                  group=group))

但这没用。不知道geom_segment是否是我应该使用的。

Answer 1

merged.data <- merge(x=start, y=df, by="group")
colnames(merged.data) <- c("group", "X.start", "Y.start", "X.end", "Y.end", "condition")

ggplot(df, aes(x=X, y=Y, color=as.character(group))) + 
  geom_point(size=2)  +
  geom_point(data=start, aes(x=X, y=Y, color=as.character(group)), size=2) +
  geom_segment(data=merged.data[merged.data$condition == "y", ], aes(x=X.start, y=Y.start, xend=X.end, yend=Y.end, color=as.character(group)))

Answer 2

library(dplyr); library(ggplot2)
start %>%
  left_join(df[df$condition=="y",], by = "group") %>%

  ggplot(aes(x = X.x, y = Y.x,
             xend = X.y, yend = Y.y, group = group)) +
  geom_segment() +
  geom_point() +
  geom_point(data = df, aes(x = X, y = Y, shape = condition), inherit.aes = F)