从ggplot2图表中移除图层 [英] Remove a layer from a ggplot2 chart

问题描述

我想从创建的ggplot2中移除图层（在本例中为 geom_ribbon 的结果）网格对象。有一种方法可以在它已经成为对象的一部分时将它移除？

  library（ggplot2）
 dat< ;  -  data.frame（x = 1：3，y = 1：3，ymin = 0：2，ymax = 2：4）
p < -  ggplot（dat，aes（x = x，y = y ））+ geom_ribbon（aes（ymin = ymin，ymax = ymax），alpha = 0.3）
 + geom_line（）
 
＃这有geom_ribbon 
p 
 
＃这覆盖了
p + geom_ribbon上的另一个功能区（aes（ymin = ymin，ymax = ymax，fill = NA））
  

我希望这个功能可以让我在较不复杂的情况下构建更复杂的情节。我使用的函数返回一个网格对象，然后在完成组装后打印出最终的绘图。基线图中有一条单独的行，并在其周围有一个相应的错误栏（ geom_ribbon ）。更复杂的情节会有多行，多个重叠的 geom_ribbon 对象会让人分心。我想用多行删除它们。此外，我将能够使用方面或其他ggplot2功能快速创建替代版本。

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编辑： 在工作时接受@ mnel的答案。现在，我需要确定如何动态访问<！c $ c> geom_ribbon 图层，该图层在SO问题中捕获

现在让我们删除标签并再次显示图：

 p < -  remove_geom（p，GeomText）
p 
  

I'd like to remove a layer (in this case the results of geom_ribbon) from a ggplot2 created grid object. Is there a way I can remove it once it's already part of the object?

library(ggplot2)
dat <- data.frame(x=1:3, y=1:3, ymin=0:2, ymax=2:4)
p <- ggplot(dat, aes(x=x, y=y)) + geom_ribbon(aes(ymin=ymin, ymax=ymax), alpha=0.3) 
     + geom_line()

# This has the geom_ribbon
p

# This overlays another ribbon on top
p + geom_ribbon(aes(ymin=ymin, ymax=ymax, fill=NA))

I'd like this functionality to allow me to build more complicated plots on top of less complicated ones. I am using functions that return a grid object and then printing out the final plot once it is fully assembled. The base plot has a single line with a corresponding error bar (geom_ribbon) surrounding it. The more complicated plot will have several lines and the multiple overlapping geom_ribbon objects are distracting. I'd like to remove them from the plots with multiple lines. Additionally, I'll be able to quickly create alternative versions using facets or other ggplot2 functionality.

---

Edit: Accepting @mnel's answer as it works. Now I need to determine how to dynamically access the geom_ribbon layer, which is captured in the SO question here.

---

Edit 2: For completeness, this is the function I created to solve this problem:

remove_geom <- function(ggplot2_object, geom_type) {
  layers <- lapply(ggplot2_object$layers, function(x) if(x$geom$objname == geom_type) NULL else x)
  layers <- layers[!sapply(layers, is.null)]

  ggplot2_object$layers <- layers
  ggplot2_object
}

解决方案

For ggplot2 version 2.2.1, I had to modify the proposed remove_geom function like this:

remove_geom <- function(ggplot2_object, geom_type) {
  # Delete layers that match the requested type.
  layers <- lapply(ggplot2_object$layers, function(x) {
    if (class(x$geom)[1] == geom_type) {
      NULL
    } else {
      x
    }
  })
  # Delete the unwanted layers.
  layers <- layers[!sapply(layers, is.null)]
  ggplot2_object$layers <- layers
  ggplot2_object
}

Here's an example of how to use it:

library(ggplot2)

set.seed(3000)
d <- data.frame(
  x = runif(10),
  y = runif(10),
  label = sprintf("label%s", 1:10)
)

p <- ggplot(d, aes(x, y, label = label)) + geom_point() + geom_text()

Let's show the original plot:

p

Now let's remove the labels and show the plot again:

p <- remove_geom(p, "GeomText")
p

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