可以向ggplot2添加第三个y轴？

Question

有可能在使用GGPLOT2的图中添加第三Y轴？ 我想在图中显示三个不同的数据源。我已经添加了第二个Y轴，对于下一个数据集，该量表再次大不相同，为什么我现在正在寻找解决方案。

到目前为止，我只找到了如何添加第二个轴，例如[此处]。 但是我是否有可能再添加一个...谢谢！

这同样笨拙，但显示了如何仅使用Cran Resources从头开始进行。

library(cowplot)
library(patchwork)

p1 <- ggplot(df, aes(Sepal.Width, Sepal.Length)) + 
                   geom_point() + theme(axis.line = element_line())
p2 <- ggplot(df, aes(Sepal.Width, Petal.Width)) + geom_point() +
                   theme(axis.line = element_line())

p3 <- ggplot(df, aes(Sepal.Width, Petal.Length)) + 
  geom_point(aes(color = "Petal.Length")) +
  geom_point(aes(y = Sepal.Length/100, color = "Sepal.Length")) +
  geom_point(aes(y = Petal.Width / 1000, color = "Petal.Width")) +
  theme(axis.line = element_line(),
        plot.margin = margin(10, 10, 10, 30))

wrap_elements(get_plot_component(p1, "ylab-l")) +
  wrap_elements(get_y_axis(p1)) +
  wrap_elements(get_plot_component(p2, "ylab-l")) +
  wrap_elements(get_y_axis(p2)) +
  p3 + 
  plot_layout(widths = c(3, 1, 3, 1, 40))

Answer 1

data使用了

df <- iris
df$Sepal.Length <- df$Sepal.Length * 100
df$Petal.Width <- df$Petal.Width * 1000

---

这是一个非常笨拙的解决方案，基于从先前绘制的图和编辑网格对象中提取元素。它可能会或不给您一个可行的解决方案。

source("https://raw.githubusercontent.com/davidearn/plague_growth/master/analysis/plots/3axes.R")
set.seed(101)
dd <- data.frame(x=rnorm(20),y=rnorm(20))
library(ggplot2)
gg0 <- ggplot(dd)
g1A <- gg0 + geom_point(aes(x,y))
g1B <- gg0 + geom_point(aes(x,10*y))
g1C <- gg0 + geom_point(aes(x,100*y))
## use return_gtable = TRUE if planning to add further axes
g2 <- combine_axes(g1A,g1B,add_pos="l", return_gtable=TRUE)
g3 <- combine_axes(g2,g1C,add_pos="l")
print(g3)

Answer 2

有一个解决方案，不会制造另一个轴，而是使用ggtext软件包将第二轴上的标签作为HTML操纵。

首先，您会找到可以重新反弹其他2个变量的系数。

## Packages
library(ggtext);library(tidyverse)

## Data
df <- data.frame(category = paste0(rep("type_", 30), c("A", "B", "C")),
                 x_val = rep(1:10, 3), y_val = abs(rnorm(30))*c(100,10,1))
## Rebase
rebase_coef <- df %>% group_by(category) %>% summarise(rebase_coef = max(y_val)) %>%
  ungroup() %>% mutate(rebase_coef = rebase_coef / max(rebase_coef))

df_rebase <- df %>% 
  mutate(y_val = case_when(category == "type_B" ~ y_val/rebase_coef$rebase_coef[2], 
                           category == "type_C" ~ y_val/rebase_coef$rebase_coef[3],
                           TRUE ~ y_val))

，然后创建一个数据框架，该数据框将使您的标签从向量中用作主轴断裂的向量（我使用一个容易将标签转换为HTML的函数）：

## Y Axis Breaks
vbreaks <- max(df$y_val)*c(1, 0.75, 0.5, 0.25, 0)

## Category colors
vcolor_cat <- c("#0077B7","#8B4500","#4DAF4A"); names(vcolor_cat) <- unique(df$category)

## HTML function
html_fun <- function(x, color = 'white', size = 12) {
  paste0("<span style = 'color:", color,";font-size:", size, "pt'><b>", x, "</b></span>")
}

## 2nd Labels
axis_labs <- data.frame(y_A = vbreaks, y_B = vbreaks/10, y_C = vbreaks/100) %>%
  mutate(ylab_txt = paste0(html_fun(round(y_B,2), color = vcolor_cat[2]), "<br>", 
                           html_fun(round(y_C,2),  color = vcolor_cat[3]) ))

Answer 3

然后您情节：

df_rebase %>% ggplot(aes(x = x_val, y = y_val, color = category)) + geom_point() +
  scale_color_manual(values = vcolor_cat) + 
  scale_y_continuous(breaks = vbreaks, labels = function(x) round(x, 2), name = "1 Thing", 
                     sec.axis = sec_axis(~.*1, labels = axis_labs$ylab_txt, breaks = vbreaks, name = "2 Things")) +
  theme(
    axis.title.y.left = element_textbox_simple(
      hjust = 0.5, vjust = 0.5, halign = 0.5, valign = 0.5,
      orientation = "left-rotated", width = 0.75, fill = "grey90",
      padding = margin(4, 2, 3, 2), margin = margin(2, 2, 2, 0)),
    axis.title.y.right = element_textbox_simple(
      hjust = 0.5, vjust = 0.5, halign = 0.5, valign = 0.5,
      orientation = "right-rotated", width = 0.75, fill = "grey90",
      padding = margin(4, 2, 3, 2), margin = margin(2, 0, 2, 2)),
    axis.text.y.left = element_markdown(
      colour = vcol_metric[1], fill = 'transparent', size = 12, face = "bold",
      hjust = 1, vjust = 0.5, halign = 1, valign = 0.5, lineheight = 0.75,
      padding = ggplot2::margin(3, 1, 1, 1), margin = ggplot2::margin(0, 0, 0, 0),
      align_widths = FALSE, align_heights = FALSE
    ),
    axis.text.y.right = element_markdown(
      fill = 'transparent', hjust = 0, vjust = 0.5, halign = 0, valign = 0.5, lineheight = 0.75,
      padding = ggplot2::margin(3, 1, 1, 1), margin = ggplot2::margin(0, 0, 0, 0),
      align_widths = FALSE, align_heights = FALSE
    ))

3y轴图

thanks to this Thread我设法构建了我需要的绘图。
我设法以特定的颜色为y轴着色。

无论如何，我一直在尝试以相同的方式（而不是默认的红色，绿色，蓝色）持续数小时，都找不到解决方案...有什么帮助吗？非常感谢！