是否可以为 geom_point 和 geom_segment 添加图例？答案

【问题标题】：Is it possible add legend for geom_point and geom_segment?是否可以为 geom_point 和 geom_segment 添加图例？
【发布时间】：2017-07-24 13:21:59
【问题描述】：

我想知道是否可以为geom_point 和geom_segment 添加图例？从 geom_point 我自动获取图例，但是我不知道如何为geom_segment 添加图例。我试过scale_linetype_manual 但显然它不起作用。

这是我的数据片段：

 df1 <- structure(list(type = c("WT", "SHC", "WT", "SHC", "WT", "SHC", 
                                   "WT", "SHC", "WT", "SHC", "WT", "SHC", "WT", "SHC", "WT", "SHC", 
                                   "WT", "SHC", "WT", "SHC", "WT", "SHC", "WT", "SHC"), lipids = structure(c(3L, 
                                                                                                             3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 
                                                                                                             3L, 3L, 3L, 3L, 3L, 3L, 3L), .Label = c("DIP", "mDIP", "CL [66:0]", 
                                                                                                                                                     "CL [70:2]", "CL [70:4]", "CL [72:4]", "CL [74:2]", "PC [32:1]", 
                                                                                                                                                     "PC [32:2]", "PC [34:1]", "PC [34:2]", "PC [34:3]", "PC [34:4]", 
                                                                                                                                                     "PC [36:2]", "PC [36:3]", "PC [36:4]", "PE [32:1]", "PE [34:1]", 
                                                                                                                                                     "PE [34:2]", "PE [36:1]", "PE [36:2]", "PE [36:3]", "PG [32:1]", 
                                                                                                                                                     "PG [34:1]", "PG [34:2]", "PG [36:2]", "PG [36:3]"), class = "factor"), 
                          rep = c("pH 5.5 1", "pH 5.5 1", "pH 5.5 2", "pH 5.5 2", "pH 5.5 3", 
                                  "pH 5.5 3", "pH 6 1", "pH 6 1", "pH 6 2", "pH 6 2", "pH 6 3", 
                                  "pH 6 3", "pH 7 1", "pH 7 1", "pH 7 2", "pH 7 2", "pH 7 3", 
                                  "pH 7 3", "pH 7.5 1", "pH 7.5 1", "pH 7.5 2", "pH 7.5 2", 
                                  "pH 7.5 3", "pH 7.5 3"), num = c(0.004633127, 0.04514786, 
                                                                   0.009330446, 0.032803203, 0.016920389, 0.045960156, 0.017778907, 
                                                                   0.028992327, 0.023182626, 0.03861396, 0.023031255, 0.04358965, 
                                                                   0.007902522, 0.01725995, 0.005021786, 0.018188753, 0.006793196, 
                                                                   0.032270599, 0.007153489, 0.06383629, 0.017068877, 0.026518865, 
                                                                   0.014697648, 0.02748779), groups = c("Ph", "Ph", "Ph", "Ph", 
                                                                                                        "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", 
                                                                                                        "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph", "Ph"
                                                                   )), row.names = c(NA, -24L), class = c("tbl_df", "tbl", "data.frame"
                                                                   ), .Names = c("type", "lipids", "rep", "num", "groups"))

这是一个代码，我到目前为止：

ph7 <- df1
ph7$rep<-sub("X","",ph7$rep)
ph7$rep<-sub("\\d$","",ph7$rep)
ph7$rep<-sub("\\.$","",ph7$rep)
ph7 <- ph7 %>% group_by(type, lipids, groups, rep)%>% summarise_all( funs(mean(.)))

pos1 <- data.frame(x1=c(0.8),
                         x2=c(1.0),
                         y1=filter(ph7, grepl('pH 7 ', rep))$num[1],
                         y2=filter(ph7, grepl('pH 7 ', rep))$num[1],
                         label=filter(ph7, grepl('pH 7 ', rep))$type[1])
pos6 <- data.frame(x1=c(1.0),
                         x2=c(1.2),
                         y1=filter(ph7, grepl('pH 7 ', rep))$num[2],
                         y2=filter(ph7, grepl('pH 7 ', rep))$num[2],
                         label=filter(ph7, grepl('pH 7 ', rep))$type[2])

ggplot(df1, aes(x = factor(lipids), y= num, col = type)) + 
  geom_point(size = 0.4, position = position_dodge(width = 0.3))+
  geom_segment(aes(x=x1,y=y1,xend=x2,yend=y2,colour=label),lwd=1,data=pos1, col = "grey50") +
  geom_segment(aes(x=x1,y=y1,xend=x2,yend=y2,colour=label),lwd=1,data=pos6, col = "grey50") + 
  scale_color_manual(name = "",values = c( "red","grey50"),labels=c( "SHC","WT"))+ 
  scale_linetype_manual("mean",values=c("mean"=2))+
  theme(legend.title=element_blank())

我想要的是下面的图，带有固定的图例。

【问题讨论】：

您是否省略了数据框ph7？我无法重现你的情节。

标签： r ggplot2

【解决方案1】：

您需要做的就是在 geom_segment 的 aes 部分添加 linetype = "mean"：

  ggplot(df1, aes(x = factor(lipids), y= num, col = type)) + 
  geom_point(size = 0.4, position = position_dodge(width = 0.3))+
  geom_segment(aes(x=x1,y=y1,xend=x2,yend=y2,colour=label, linetype = "mean"),lwd=1,data=pos1, col = "grey50") +
  geom_segment(aes(x=x1,y=y1,xend=x2,yend=y2,colour=label, linetype = "mean"),lwd=1,data=pos6, col = "grey50",) + 
  scale_color_manual(name = "",values = c( "red","grey50"),labels=c( "SHC","WT"))+ 
  scale_linetype_manual("mean",values=c("mean"=1))+
  theme(legend.title=element_blank())

【讨论】：