r - 使用ggplot2的组合箱线图和直方图

我试图结合直方图和箱线图以可视化连续变量。这是我到目前为止的代码

require(ggplot2)
require(gridExtra)
p1 = qplot(x = 1, y = mpg, data = mtcars, xlab = "", geom = 'boxplot') +
     coord_flip()
p2 = qplot(x = mpg, data = mtcars, geom = 'histogram')
grid.arrange(p2, p1, widths = c(1, 2))

除了x轴的对齐方式，它看起来还不错。谁能告诉我如何调整它们？
或者，如果有人有更好的方法使用ggplot2制作此图，也将不胜感激。

最佳答案

您可以通过ggExtra中的coord_cartesian()和align.plots来实现。

library(ggplot2)
library(ggExtra) # from R-forge

p1 <- qplot(x = 1, y = mpg, data = mtcars, xlab = "", geom = 'boxplot') +
  coord_flip(ylim=c(10,35), wise=TRUE)
p2 <- qplot(x = mpg, data = mtcars, geom = 'histogram') +
  coord_cartesian(xlim=c(10,35), wise=TRUE)

align.plots(p1, p2)

这是align.plot的修改版本，用于指定每个面板的相对大小:

align.plots2 <- function (..., vertical = TRUE, pos = NULL)
{
    dots <- list(...)
    if (is.null(pos)) pos <- lapply(seq(dots), I)
    dots <- lapply(dots, ggplotGrob)
    ytitles <- lapply(dots, function(.g) editGrob(getGrob(.g,
        "axis.title.y.text", grep = TRUE), vp = NULL))
    ylabels <- lapply(dots, function(.g) editGrob(getGrob(.g,
        "axis.text.y.text", grep = TRUE), vp = NULL))
    legends <- lapply(dots, function(.g) if (!is.null(.g$children$legends))
        editGrob(.g$children$legends, vp = NULL)
    else ggplot2:::.zeroGrob)
    gl <- grid.layout(nrow = do.call(max,pos))
    vp <- viewport(layout = gl)
    pushViewport(vp)
    widths.left <- mapply(`+`, e1 = lapply(ytitles, grobWidth),
        e2 = lapply(ylabels, grobWidth), SIMPLIFY = F)
    widths.right <- lapply(legends, function(g) grobWidth(g) +
        if (is.zero(g))
            unit(0, "lines")
        else unit(0.5, "lines"))
    widths.left.max <- max(do.call(unit.c, widths.left))
    widths.right.max <- max(do.call(unit.c, widths.right))
    for (ii in seq_along(dots)) {
        pushViewport(viewport(layout.pos.row = pos[[ii]]))
        pushViewport(viewport(x = unit(0, "npc") + widths.left.max -
            widths.left[[ii]], width = unit(1, "npc") - widths.left.max +
            widths.left[[ii]] - widths.right.max + widths.right[[ii]],
            just = "left"))
        grid.draw(dots[[ii]])
        upViewport(2)
    }
}

用法:

# 5 rows, with 1 for p1 and 2-5 for p2
align.plots2(p1, p2, pos=list(1,2:5))
# 5 rows, with 1-2 for p1 and 3-5 for p2
align.plots2(p1, p2, pos=list(1:2,3:5))