使用 ggplot2 拆分小提琴图

本文介绍了使用 ggplot2 拆分小提琴图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我想使用 ggplot 创建一个分割小提琴密度图，就像

这是一些数据:

set.seed(20160229)my_data = data.frame(y=c(rnorm(1000), rnorm(1000, 0.5), rnorm(1000, 1), rnorm(1000, 1.5)),x=c(rep('a', 2000), rep('b', 2000)),m=c(rep('i', 1000), rep('j', 2000), rep('i', 1000)))

我可以像这样绘制躲避的小提琴:

library('ggplot2')ggplot(my_data, aes(x, y, fill=m)) +geom_violin()

但是很难直观地比较并排分布中不同点的宽度.我在 ggplot 中找不到任何分离小提琴的例子 - 有可能吗?

我找到了一个

I'd like to create a split violin density plot using ggplot, like the fourth example on this page of the seaborn documentation.

Here is some data:

set.seed(20160229) my_data = data.frame( y=c(rnorm(1000), rnorm(1000, 0.5), rnorm(1000, 1), rnorm(1000, 1.5)), x=c(rep('a', 2000), rep('b', 2000)), m=c(rep('i', 1000), rep('j', 2000), rep('i', 1000)) )

I can plot dodged violins like this:

library('ggplot2') ggplot(my_data, aes(x, y, fill=m)) + geom_violin()

But it's hard to visually compare the widths at different points in the side-by-side distributions. I haven't been able to find any examples of split violins in ggplot - is it possible?

I found a base R graphics solution but the function is quite long and I want to highlight distribution modes, which are easy to add as additional layers in ggplot but will be harder to do if I need to figure out how to edit that function.

解决方案

Or, to avoid fiddling with the densities, you could extend ggplot2's GeomViolin like this:

GeomSplitViolin <- ggproto("GeomSplitViolin", GeomViolin, draw_group = function(self, data, ..., draw_quantiles = NULL) { data <- transform(data, xminv = x - violinwidth * (x - xmin), xmaxv = x + violinwidth * (xmax - x)) grp <- data[1, "group"] newdata <- plyr::arrange(transform(data, x = if (grp %% 2 == 1) xminv else xmaxv), if (grp %% 2 == 1) y else -y) newdata <- rbind(newdata[1, ], newdata, newdata[nrow(newdata), ], newdata[1, ]) newdata[c(1, nrow(newdata) - 1, nrow(newdata)), "x"] <- round(newdata[1, "x"]) if (length(draw_quantiles) > 0 & !scales::zero_range(range(data$y))) { stopifnot(all(draw_quantiles >= 0), all(draw_quantiles <= 1)) quantiles <- ggplot2:::create_quantile_segment_frame(data, draw_quantiles) aesthetics <- data[rep(1, nrow(quantiles)), setdiff(names(data), c("x", "y")), drop = FALSE] aesthetics$alpha <- rep(1, nrow(quantiles)) both <- cbind(quantiles, aesthetics) quantile_grob <- GeomPath$draw_panel(both, ...) ggplot2:::ggname("geom_split_violin", grid::grobTree(GeomPolygon$draw_panel(newdata, ...), quantile_grob)) } else { ggplot2:::ggname("geom_split_violin", GeomPolygon$draw_panel(newdata, ...)) } }) geom_split_violin <- function(mapping = NULL, data = NULL, stat = "ydensity", position = "identity", ..., draw_quantiles = NULL, trim = TRUE, scale = "area", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE) { layer(data = data, mapping = mapping, stat = stat, geom = GeomSplitViolin, position = position, show.legend = show.legend, inherit.aes = inherit.aes, params = list(trim = trim, scale = scale, draw_quantiles = draw_quantiles, na.rm = na.rm, ...)) }

And use the new geom_split_violin like this:

ggplot(my_data, aes(x, y, fill = m)) + geom_split_violin()