ggplot2为facet plot中的两个Y轴添加单独的图例 [英] ggplot2 add separate legend each for two Y axes in facet plot

问题描述

我试图在轴标题旁添加传说。我遵循

解决方案

为了缩短这一点，我减少了您的主题定义。

---

我利用了可以从ggplot元素中提取单个grob的事实。在这种情况下，我们提取3个传说。

对于所需的结果，我们需要创建4个图：

1. em> p ：一个没有图例的图


2. 绘制 l1 绘制 l2 ：蓝色传说的图


3. 绘制 l3 ：红色图例的图
$ b $我们使用函数 get_legend（），它是程序包中的一部分。
$ b> cowplot 。它可以让你提取一个情节的图例。




在我们提取左边的两个图例后，我们使用 arrangeGrob 合并它们并命名组合图例 llegend 。
在我们提取红色图例之后，我们使用 grid.arrange 来绘制所有三个对象（ llegend ， p 和 rlegend ）。



关于图例键的方向，您应该注意到我们在相应的图上打印了图例。这样，我们可以使用 editGrob 在提取它们之后旋转（组合）图例，并且图例按键具有正确的方向。



这是所有的代码：



  library（ggplot2）
 library（gridExtra）
 library （grid）
 library（cowplot）
 
＃没有图例的实际情节
p < -  ggplot（mapping = aes（x = plate_num，y = value，group = variable）） + 
 geom_line（data = subset（df1，变量％in％c（'Before Treatment'，'After Treatment'）），aes（color = variable），size = 1，show.legend = F）+ 
 geom_point（data = subset（df1，变量％in％c（'Before Treatment'，'After Treatment'）），aes（color = variable），size = 2，show.legend = F）+ 
 
 geom_line（data = subset（df1，变量％in％c（'norm_ratio'）），aes（color ='Test'），col ='red'，size = 1）+ 
 geom_point （data = subset（df1，variable％in％c（'norm_ratio'）），aes（color ='Test'），col ='red'，size = 2）+ 
 facet_wra p（〜grp）+ 
 scale_y_continuous（sec.axis = sec_axis（trans =〜。 *（max2 / max1），
 name ='治疗前后主效应比例'）+ 
 scale_color_manual（values = c（'green'，'blue'），guide ='legend'）+ 
 theme_bw（）+ 
 theme（axis.text.x = element_text（size = 11，face =bold，angle = 0，vjust = 1），
 axis.title.x = element_text（size = 11，face =bold），
 axis.text.y = element_text（size = 11，face =bold，color ='black'），
 axis.text.y.right = element_text（size = 11，face =bold，color ='red'），
 axis.title.y.right = element_text（size = 11，face = bold，color ='red'，margin = margin（0,0,0,0）），
 axis.title.y = element_text（size = 11，face =bold，margin = margin（ 0，-30,0,0）），
 panel.grid.minor = element_blank（），
 strip.text.x = element_text（size = 15，face =bold，color =黑色，角度= 0），
 plot.margin =单位（c（1,1,1,1），cm））+ 
 ylab（'TDP43 \\\
\\\
\\\
'）+ 
 xlab（'\ nPlate Number'）
 
＃在左边创建图例
 l1<  -  ggplot（mapping = aes（x = plate_num，y = value，group = variable））+ 
 geom_line（data = subset（df1，变量％in％c（'Before Treatment'）），aes（color = variable） = 1，show.legend = TRUE）+ 
 geom_point（data = subset（df1，变量％in％c（'Before Treatment'）），aes（color = variable），size = 2，show.legend = TRUE）+ 
 scale_color_manual（values ='green'，guide ='legend'）+ 
 theme（legend.direction ='horizo​​ntal'，
 legend.text = element_text（angle = 0， color = c（'green'，'blue'）），
 legend.position ='top'，
 legend.title = element_blank（），
 legend.margin = margin（0， 0，0，'cm'），
 legend.box.margin =单位（c（0，0，-2.5，0），'cm'））
 
 l2< ;  -  ggplot（mapping = aes（x = plate_num，y = value，group = variable））+ 
 geom_line（data = subse t（df1，变量％in％c（'After Treatment'）），aes（color = variable），size = 1，show.legend = TRUE）+ 
 geom_point（data = subset（df1，variable％in ％c（'After Treatment'）），aes（color = variable），size = 2，show.legend = TRUE）+ 
 scale_color_manual（values ='blue'，guide ='legend'）+ 
 theme（legend.direction ='horizo​​ntal'，
 legend.text = element_text（angle = 0，color = c（'blue'）），
 legend.position ='top'，
 legend.title = element_blank（），
 legend.margin = margin（0，0，0，'cm'），
 legend.box.margin = unit（c（0，0， 'cm'））
 
 legend1<  -  get_legend（l1）
 legend2<  -  get_legend（l2）
 
＃组合绿色和蓝色图例
legend < -  editGrob（arrangeGrob（grobs = list（legend1，legend2），
 nrow = 1，ncol = 2），vp = viewport（angle = 90））
 
＃在右侧绘制图例
 l3 < -  ggplot（mapping = aes（x = plat e_num，y = value，group = variable））+ 
 geom_line（data = subset（df1，变量％in％c（'norm_ratio'）），aes（color = variable），size = 1）+ 
 geom_point（data = subset（df1，变量％in％c（'norm_ratio'）），aes（color = variable），size = 2）+ 
 scale_color_manual（values ='red'，guide ='legend '）+ 
主题（legend.direction ='horizo​​ntal'，
 legend.text = element_text（angle = 0，color ='red'），
 legend.position ='top'， 
 legend.title = element_blank（），
 legend.margin = margin（0，0，0，'cm'），
 legend.box.margin = unit（c（0 ，0，-3,0），'cm'））
 
＃提取图例
 rlegend<  -  editGrob（get_legend（l3），vp = viewport（angle = 270））
 
 grid.arrange（grobs = list（llegend，p，rlegend），ncol = 3，
 widths = unit（c（3，16，3），cm））
  




I am trying to add legends next to axis titles. I followed this stackoverflow answer to get the plot.

How to add legend on two y axes?. I would like to have legend on both left and right Y-axes. In the plot below, the right y-axis lacks legend symbols.

Also is it possible to give unique color for text similar to symbols in legend.

At the same time, how to rotate legend key symbols to vertical position?

The code I have so far:

## install ggplot2 as follows:
# install.packages("devtools")
# devtools::install_github("hadley/ggplot2")

packageVersion('ggplot2')
# [1] ‘2.2.0.9000’

packageVersion('data.table')
# [1] ‘1.9.7’

# libraries
library(ggplot2)
library(data.table)

# data
df1 <- structure(list(plate_num = c(1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L,
                                    1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L), 
                      `Before Treatment` = c(662.253098499674, 684.416067929458, 688.284595300261, 
                                             692.532637075718, 728.988910632746, 684.708496732026, 
                                             703.390706806283, 673.920966688439, 644.945573770492, 504.423076923077, 
                                             580.263743455497, 580.563767168084, 689.6014445174, 804.740789473684, 
                                             815.792020928712, 789.234139960759, 778.087753765553, 745.777922926192, 
                                             787.762434554974, 780.828758169935, 781.265839320705, 732.683552631579, 
                                             773.964052287582, 713.941253263708, 724.459070072037, 838.899148657498),
                      `After Treatment` = c(440.251141552511, 431.039190071848, 460.349216710183, 479.798955613577, 
                                            441.123939986954, 436.17908496732, 453.938481675393, 437.237753102547,
                                            448.52, 426.70925684485, 390.417539267016, 359.66121648136, 451.969796454366, 
                                            515.611842105263, 542.325703073904, 547.637671680837, 518.316306483301, 478.536903984324, 
                                            501.122382198953, 494.475816993464, 474.581319399086, 438.515789473684, 
                                            440.251633986928, 407.945822454308, 413.571054354944, 537.290111329404),
                      Ratio = c(1.50426208132996, 1.58782793698034, 1.49513580194398, 1.443380876455, 1.6525716347526, 
                                1.56978754903694, 1.54952870311901, 1.54131467812749, 1.43794161636157, 1.18212358609901, 1.48626453756382, 
                                                 1.61419619509676, 1.5257688675819, 1.5607492376201, 1.50424738548219, 
                                                 1.44116115594897, 1.50118324280547, 1.55845435684647, 1.57199610821259, 
                                                 1.57910403569899, 1.64622122149676, 1.67082593197148, 1.75800381540563, 
                                                 1.75008840381905, 1.75171608951693, 1.56135229547), 
                      grp = c("wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X", "wt-3X",
                              "wt-3X", "wt-3X", "wt-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X", 
                              "mu-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X", "mu-3X")),
                 .Names = c("plate_num", "Before Treatment", "After Treatment", "Ratio", "grp"),
                 row.names = c(NA, -26L), class = "data.frame")


max1 <- max(c(df1$`Before Treatment`, df1$`After Treatment`))
max2 <- max(df1$Ratio)
df1$norm_ratio <- df1$Ratio / (max2/max1)
df1 <- melt(df1, id = c("plate_num", 'grp'))
df1$plate_num <- factor(df1$plate_num, levels = 1:13, ordered = TRUE)

# plot
p <- ggplot(mapping = aes(x = plate_num, y = value, group = variable)) +
  geom_line(data = subset(df1, variable %in% c('Before Treatment', 'After Treatment')), aes(color = variable), size = 1, show.legend = TRUE) +
  geom_point(data = subset(df1, variable %in% c('Before Treatment', 'After Treatment')), aes(color = variable), size = 2, show.legend = TRUE) +
  scale_color_manual(values = c('green', 'blue'), guide = 'legend') + 
  geom_line(data = subset(df1, variable %in% c('norm_ratio')), aes(color = variable), col = 'red', size = 1) +
  geom_point(data = subset(df1, variable %in% c('norm_ratio')), aes(color = variable), col = 'red', size = 2) +
  facet_wrap(~ grp) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * (max2 / max1),
                                         name = 'Ratio of Main Effect of Before and After Treatment\n')) +

  theme_bw() + 
  theme(axis.text.x = element_text(size=15, face="bold", angle = 0, vjust = 1), 
        axis.title.x = element_text(size=15, face="bold"),
        axis.text.y = element_text(size=15, face="bold", color = 'black'),
        axis.text.y.right = element_text(size=15, face="bold", color = 'red'),
        axis.title.y.right = element_text(size=15, face="bold", color = 'red'),
        axis.title.y = element_text(size=15, face="bold"),
        axis.ticks.length=unit(0.5,"cm"),
        legend.position = c(-0.28, 0.4),
        legend.direction = 'vertical',
        legend.text = element_text(size = 15, angle = 90),
        legend.key = element_rect(color = NA, fill = NA),
        legend.key.width=unit(2,"line"),
        legend.key.height=unit(2,"line"),
        legend.title = element_blank(),
        panel.grid.major = element_blank(), 
        panel.grid.minor = element_blank(),
        strip.text.x = element_text(size=15, face="bold", color = "black", angle = 0),
        plot.margin = unit(c(1,4,1,3), "cm")) +
  ylab('Main Effect of TDP43\n\n\n') + 
  xlab('\nPlate Number')

print(p)

解决方案

In order to make this a bit shorter I cut down your theme definitions.

---

I make use of the fact that you can extract single grobs from your ggplot elements. In this case we extract 3 legends.

For the desired result we need to create 4 plots:

1. Plot p: a plot without legends
2. Plot l1: a plot for the green legend
3. Plot l2: a plot for the blue legend
4. Plot l3: a plot for the red legend

We make use of the function get_legend() which is part of the package cowplot. It lets you extract the legend of a plot.

After we extracted both legends for the left side we use arrangeGrob to combine them and name that combined legend llegend. After we extracted the red legend, we us grid.arrange to plot all three objects (llegend, p and rlegend).

Concerning the orientation of the legend keys you should notice that we print the legends on top of the corresponding plots. That way we can use editGrob to rotate the (combined) legends after extracting them and the legend keys have the correct orientation.

This is all the code:

library(ggplot2)
library(gridExtra)
library(grid)
library(cowplot)

# actual plot without legends
p <- ggplot(mapping = aes(x = plate_num, y = value, group = variable)) +
  geom_line(data = subset(df1, variable %in% c('Before Treatment', 'After Treatment')), aes(color = variable), size = 1, show.legend = F) +
  geom_point(data = subset(df1, variable %in% c('Before Treatment', 'After Treatment')), aes(color = variable), size = 2, show.legend = F) +

  geom_line(data = subset(df1, variable %in% c('norm_ratio')), aes(color = 'Test'), col = 'red', size = 1) +
  geom_point(data = subset(df1, variable %in% c('norm_ratio')), aes(color = 'Test'), col = 'red', size = 2) +
  facet_wrap(~ grp) +
  scale_y_continuous(sec.axis = sec_axis(trans = ~ . * (max2 / max1),
                                         name = 'Ratio of Main Effect of Before and After Treatment\n')) +
  scale_color_manual(values = c('green', 'blue'), guide = 'legend') +
  theme_bw() + 
  theme(axis.text.x = element_text(size=11, face="bold", angle = 0, vjust = 1), 
        axis.title.x = element_text(size=11, face="bold"),
        axis.text.y = element_text(size=11, face="bold", color = 'black'),
        axis.text.y.right = element_text(size=11, face="bold", color = 'red'),
        axis.title.y.right = element_text(size=11, face="bold", color = 'red', margin=margin(0,0,0,0)),
        axis.title.y = element_text(size=11, face="bold", margin=margin(0,-30,0,0)),
        panel.grid.minor = element_blank(),
        strip.text.x = element_text(size=15, face="bold", color = "black", angle = 0),
        plot.margin = unit(c(1,1,1,1), "cm")) +
  ylab('Main Effect of TDP43\n\n\n') + 
  xlab('\nPlate Number')

# Create legend on the left 
l1 <- ggplot(mapping = aes(x = plate_num, y = value, group = variable)) +
  geom_line(data = subset(df1, variable %in% c('Before Treatment')), aes(color = variable), size = 1, show.legend = TRUE) +
  geom_point(data = subset(df1, variable %in% c('Before Treatment')), aes(color = variable), size = 2, show.legend = TRUE) +
  scale_color_manual(values = 'green', guide = 'legend') +
  theme(legend.direction = 'horizontal', 
        legend.text = element_text(angle = 0, colour = c('green', 'blue')),
        legend.position = 'top',
        legend.title = element_blank(),
        legend.margin = margin(0, 0, 0, 0, 'cm'),
        legend.box.margin = unit(c(0, 0 , -2.5 ,0), 'cm'))

l2 <- ggplot(mapping = aes(x = plate_num, y = value, group = variable)) +
  geom_line(data = subset(df1, variable %in% c('After Treatment')), aes(color = variable), size = 1, show.legend = TRUE) +
  geom_point(data = subset(df1, variable %in% c('After Treatment')), aes(color = variable), size = 2, show.legend = TRUE) +
  scale_color_manual(values = 'blue', guide = 'legend') +
  theme(legend.direction = 'horizontal', 
        legend.text = element_text(angle = 0, colour = c('blue')),
        legend.position = 'top',
        legend.title = element_blank(),
        legend.margin = margin(0, 0, 0, 0, 'cm'),
        legend.box.margin = unit(c(0, 0 , -2.5 ,0), 'cm'))

legend1 <- get_legend(l1)
legend2 <- get_legend(l2)

# Combine green and blue legend
llegend <- editGrob(arrangeGrob(grobs = list(legend1, legend2), 
                       nrow = 1, ncol = 2), vp = viewport(angle = 90))

# Plot with legend on the right
l3 <- ggplot(mapping = aes(x = plate_num, y = value, group = variable)) +
   geom_line(data = subset(df1, variable %in% c('norm_ratio')), aes(color = variable), size = 1) +
  geom_point(data = subset(df1, variable %in% c('norm_ratio')), aes(color = variable), size = 2) +
  scale_color_manual(values = 'red', guide = 'legend') +
  theme(legend.direction = 'horizontal', 
        legend.text = element_text(angle = 0, colour = 'red'),
        legend.position = 'top',
        legend.title = element_blank(),
        legend.margin = margin(0, 0, 0, 0, 'cm'),
        legend.box.margin = unit(c(0, 0, -3, 0), 'cm'))

# extract legend
rlegend <- editGrob(get_legend(l3), vp = viewport(angle = 270))

grid.arrange(grobs = list(llegend, p, rlegend), ncol = 3, 
             widths = unit(c(3, 16, 3), "cm"))

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