R& ggplot2：如何获取轴标签下的箭头？ [英] R & ggplot2: How to get arrows under the axis label?

问题描述

我将用R / ggplot2绘制比值比，并且我想在X轴标签的下面或旁边添加两个箭头。一个指向左边，一个指向右边，表现出去/增加的影响力。我尝试了很多东西，比如geom_path，geom_line，但没有取得很大的成功。
这是我的代码：

  forest < -  function（d，xlab =Odds Ratio，ylab = 影响变量）{
 require（ggplot2）
p < -  ggplot（d，aes（x = ordered（x，levels = rev（x）），y = y，ymin = ylo，ymax = yhi））+ 
 geom_pointrange（）+ 
 geom_segment（aes（x = 0，xend = 0，y = 1，yend = 2））+ 
 coord_flip（）+ 
 geom_hline（aes（yintercept = 1），lty = 2）+ 
 ylab（xlab）+ 
 xlab（ylab）+ 
 scale_y_log10（）
 return（p）
 
 ##测试数据
 data < -  data.frame（x = c（A，B，C，D，E，F ，G，H，I），
y = c（1.782,0.136,0.978,0.645,0.518,1.474,0.855,0.673,0.369））
 data < -  transform（数据ylo =（0.719,0.046,0.945,0.295,0.188,0.577,0.407,0.310,0.145），
 yhi = c（4.420,0.398,1.012,1.411,1.424,3.768,1.798,1.460,0.940） ）
 forest（data）
  

添加一行如
geom_line（aes（ x = 1），箭头=箭头（长度=单位（0.15，厘米）），颜色=黑色，大小= 1）
带来了一些箭头，但他们与我的原始数据相冲突。

预先感谢您的解决方案，帮助或提示！

Marc

解决方案

这是一篇非常古老的文章，但我认为我会分享另一种选择，绊倒在这。

我有一种情况，确实需要在绘图区域之外有箭头（并且不需要涉及 grid ）。如下所示，使用表达式和符号对于某些人来说可能是一个不错的选择：

  p1 < -  qplot（x = 0： 12，y = 0:12，geom =blank）
 p1 <-p1 + ylab（表达式（符号（'\256'）））
 p1 < -  p1 + xlab表达式（符号（'\ 256'）））
 p1 < -  p1 + theme（axis.title.y = element_text（size = 30））
 p1 < -  p1 + theme .title.x = element_text（size = 30））
 
 p1 
  

主题修改aren'绝对有必要，但你可能会想要至少增加箭头的大小。

默认情况下，符号（）函数使用本文档中概述的Adobe Symbol代码： http://goo.gl/vRzpJU

如果你想要添加一些文本到标签（只是添加到表达式可能会使它太大），下面应该让你开始：

  grid.text（label =X，x = 0.645，y = 0.02）
 grid.text（label =Y，x = 0.1，y = 0.5，rot = 90）
 grid.gedit（GRID.text，gp = gpar（fontsize = 15））
  

I'm about to plot odds ratios with R/ggplot2 and I want to add two arrows underneath or next to the X-axis label. One pointing to the left, one pointing to the right, showing de-/increasing influence. I've tried lots of things, like geom_path, geom_line, without great success. This is my code:

forest <- function(d, xlab="Odds Ratio", ylab="Influencing variables"){
require(ggplot2)
p <- ggplot(d, aes(x=ordered(x, levels=rev(x)), y=y, ymin=ylo, ymax=yhi)) +
geom_pointrange() +
geom_segment(aes(x = 0, xend = 0, y= 1, yend= 2)) +
coord_flip() +
geom_hline(aes(yintercept=1), lty=2) +
ylab(xlab) +
xlab(ylab) +
scale_y_log10() 
return(p)
}
##Test Data
data <- data.frame( x   = c("A","B","C","D","E","F","G","H","I"),
                y   = c(1.782,0.136,0.978,0.645,0.518,1.474,0.855,0.673,0.369))
data <- transform(data, ylo = (0.719,0.046,0.945,0.295,0.188,0.577,0.407,0.310,0.145), 
        yhi = c(4.420,0.398,1.012,1.411,1.424,3.768,1.798,1.460,0.940))
forest(data)

Adding a line like geom_line(aes(x=1), arrow=arrow(length=unit(0.15,"cm")), colour="black", size=1) brings some arrows but they collide with my original data.
Thanks in advance for your solution, help or hint!
Marc

解决方案

This is a pretty old post, but thought I would share another option for anyone who stumbles upon this.

I have a situation which really requires that I have arrows outside of the plotting region (and don't care to involve grid). As shown below, using expressions and symbols might be a good option for some:

p1 <- qplot(x = 0:12, y = 0:12, geom = "blank") 
p1 <- p1 + ylab(expression(symbol('\256')))
p1 <- p1 + xlab(expression(symbol('\256')))
p1 <- p1 + theme(axis.title.y = element_text(size = 30))
p1 <- p1 + theme(axis.title.x = element_text(size = 30))

p1  

The theme modifications aren't absolutely necessary but you will probably want to increase the size of the arrows at least a bit.

By default, the symbol() function takes Adobe Symbol codes which are outlines in this document: http://goo.gl/vRzpJU

If you want to add some text to the labels (just adding to the expression would probably make it too big), the following should get you started:

grid.text(label="X", x = 0.645, y = 0.02)
grid.text(label="Y", x = 0.1, y = 0.5, rot=90)
grid.gedit("GRID.text", gp=gpar(fontsize=15))

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