消除垂直线ggplot

Question

以前有人问过这个问题，但答案并不总是很清楚或很复杂。我希望新版本的 ggplot2 能够带来更简单的解决方案。

如何在不消除轴刻度线或标签的情况下仅消除 ggplot 的垂直线？这对于条形图来说真的很好，因为它可以消除图形中一些不必要的干扰。

这里有一些示例代码来帮助讨论：

library(ggplot2)
set.seed(10)
CO3 <- data.frame(id=1:nrow(CO2), CO2[, 2:3], 
           outcome=factor(sample(c('none', 'some', 'lots', 'tons'), 
           nrow(CO2), rep=T), levels=c('none', 'some', 'lots', 'tons')))
CO3
x <- ggplot(CO3, aes(x=outcome)) + geom_bar(aes(x=outcome))+ 
     facet_grid(Treatment~Type, margins='Treatment', scales='free') 
x +  theme_bw() + opts(axis.text.x=theme_text(angle= 45, vjust=1, hjust= 1))

Answer 1

试试这个，重新定义 guide_grid。

此解决方案来自Cookbook for R

# Save the original definition of the guide_grid
guide_grid_orig <- ggplot2:::guide_grid

# Create the replacement function
guide_grid_no_vline <- function(theme, x.minor, x.major, y.minor, y.major) {  
  x.minor <- setdiff(x.minor, x.major)
  y.minor <- setdiff(y.minor, y.major)

  ggname("grill", grobTree(
    theme_render(theme, "panel.background"),
    if(length(y.minor) > 0) theme_render(
      theme, "panel.grid.minor", name = "y",
      x = rep(0:1, length(y.minor)), y = rep(y.minor, each=2), 
      id.lengths = rep(2, length(y.minor))
      ),
    if(length(y.major) > 0) theme_render(
      theme, "panel.grid.major", name = "y",
      x = rep(0:1, length(y.major)), y = rep(y.major, each=2), 
      id.lengths = rep(2, length(y.major))
      )
    ))
}
# Set the environment to be the same as original
environment(guide_grid_no_vline) <- environment(ggplot2:::guide_grid)

# Assign the function inside ggplot2
assignInNamespace("guide_grid", guide_grid_no_vline, ns="ggplot2")

# Draw the plot with the redefined guide_grid
ggplot(CO3, aes(x=outcome)) + 
  geom_bar(aes(x=outcome))+ 
  facet_grid(Treatment~Type, margins='Treatment', scales='free')  +
  theme_bw() + 
  opts(axis.text.x=theme_text(angle= 45, vjust=1, hjust= 1))

# Restore the original guide_grid function so that it will draw all gridlines again
assignInNamespace("guide_grid", guide_grid_orig, ns="ggplot2")