线条的传说但不填充ggplot2

时间:2015-02-18 18:44:46

标签: r ggplot2

我使用ggplot2按月创建直方图。我能够很容易地得到我想要的情节结构,但似乎无法让传说变得非常正确。

理想情况下,我可以抑制与直方图填充相关联的图例,因为该信息通过构面标题显而易见。我希望有一个关于我画的垂直线的图例,一个在零,一个在每个组的平均值。

这里的一些代码让我非常接近,但我似乎无法得到传奇。在过去,我在scale_color_manual()取得了成功,但它似乎让我失望(即我似乎在这里让它失望)。

library(ggplot2)
set.seed(232)

## Data that are somewhat similar to mine
df = data.frame(var=c(rnorm(250, 0.5, 1), 
                      rnorm(250, 1.1, 1), 
                      rnorm(250),
                      rnorm(250, -0.8, 1)),
                month=factor(c(rep('Jan', 250),
                               rep('Feb', 250),
                               rep('Mar', 250),
                               rep('Apr', 250)),
                             levels=c('Jan', 'Feb', 
                                      'Mar', 'Apr')))

## I couldn't get ggplot2 to calculate the means within an aes() call,
## so I'm calculating them myself using aggregate
means = aggregate(var ~ month, df, mean)

## Vector of colors with names I want in legend
cols = c('Zero'='black', 'Mean'='#990000')

## Current plot code that doesn't quite give me what I want.
## This is missing the legend from scale_color_manual() for the vlines
hists = ggplot(data=df) +
  geom_histogram(aes(var, fill=month)) +
  facet_wrap( ~ month) + 
  geom_vline(aes(xintercept=0, color='Zero')) +
  geom_vline(aes(xintercept=var, color='Mean'), data=means) +
  scale_color_manual(name='', values=cols) +
  guides(fill=FALSE)
print(hists)

这里没有传说,它目前的样子。我想要这样,但有垂直线的图例: My almost complete plot that is missing a legend for the vertical lines 有什么建议?谢谢!

1 个答案:

答案 0 :(得分:1)

尝试将means修改为:

> means
  month         var   col
1   Jan  0.53487078   red
2   Feb  1.16130990   red
3   Mar  0.06391861   red
4   Apr -0.76902156   red
5   Jan  0.00000000 black
6   Feb  0.00000000 black
7   Mar  0.00000000 black
8   Apr  0.00000000 black

...然后试试这个:

hists = ggplot(data=df) +
  geom_histogram(aes(var, fill=month)) +
  facet_wrap( ~ month) + 
  geom_vline(aes(xintercept=var, color=col), data=means,show_guide = TRUE) +
  scale_color_manual(name='', values=c('black','red')) +
  guides(fill=FALSE)
print(hists)

...然后调整数据框列col以使图例说出您想要的内容。

从OP编辑 - 最终代码:

library(ggplot2)
set.seed(232)
df = data.frame(var=c(rnorm(250, 0.5, 1), 
                      rnorm(250, 1.1, 1), 
                      rnorm(250),
                      rnorm(250, -0.8, 1)),
                month=factor(c(rep('Jan', 250),
                               rep('Feb', 250),
                               rep('Mar', 250),
                               rep('Apr', 250)),
                             levels=c('Jan', 'Feb', 
                                      'Mar', 'Apr')))

means = aggregate(var ~ month, df, mean)
means$col = rep('Mean', nrow(means))
means = rbind(means, data.frame(month=means$month,
                                var=rep(0, nrow(means)),
                                col=rep('Zero', nrow(means))))
cols = c('Mean'='#990000', 'Zero'='black')
hists = ggplot(data=df) +
  geom_histogram(aes(var, fill=month)) +
  facet_wrap( ~ month) + 
  geom_vline(aes(xintercept=var, color=col), data=means, show_guide=TRUE) +
  scale_color_manual(name='', values=cols) +
  guides(fill=FALSE)
print(hists)