ggplot2 guide_color_bar无法在图例元素的开头和结尾放置标签

Question

我正在尝试根据以下代码使用scale_color_gradientn (ggplot2 package)绘制从1到6的一些数据范围。默认情况下，guide_color_bar会将标签放在图例中垃圾箱的“中心”（请参见代码块1）。但是我想将标签设置为每个垃圾箱的“上”和“下”边界。我尝试相应地设置中断和标签，但是2,3,4,5正确对齐，但是1,6没有显示（请参见代码block2）。

请参阅随附的代码。

library(ggplot2)

###provide dataset 
dat    <- data.frame(list(x = c(0.214137620411313,0.553775825041679,-1.0595195186151,
                                -1.61004932625145,-0.338151062634607,0.204937753426245,
                                -0.224345039271189,-0.909609704018834,-0.808109884248038,
                                0.553083514142192,-0.389177932603183,-0.447245638594407,
                                -0.0211388451690059,-0.599417455124725,-0.310866189554078,
                                -0.681632468885545,-0.202055723512808,1.11680032924059,0.82599921267075,1.2509189798129),
                          y = c(2.60809809498069,-0.051039961195504,2.22719419433773,-0.0138721238155097,-1.54739969676097,
                                -1.37988910915699,1.47987074083825,-0.254921944338877,-0.326280380145921,-0.726638665692272,
                                -1.95234864995199,0.422940041768889,1.18168478575317,0.91795937727616,0.0954675468852296,
                                -1.68443178674375,0.990329350606127,-0.707831781928625,-0.594029169314093,-1.06589703339072)),
                     z = c(1,3,3,1,2,2,2,4,2,1,1,1,1,5,2,4,3,4,1,4))
###define breaks and colors

my_breaks <- c(0,1,2,3,4,5,6)
colors <- c('#e41a1c','#377eb8','#4daf4a',
            '#ff7f00','#ffff33','#a65628')
###the label is in the center.
ggplot(dat, aes(x,y,color=z, label = round(z,2))) + geom_point() +
  scale_color_gradientn(
    colours = colors,
    values  = scales::rescale(c(1:6)),
    limit   = c(1,6),

    guide = guide_colourbar(nbin = 6, raster = FALSE, frame.colour = "black", ticks.colour = NA,
                            direction = "horizontal", 
                            barwidth = 30, barheight = 2, label.hjust = 0)) + 
  geom_text() +
  theme(legend.position = 'bottom')

###the label shows the upper and lower boundary for each bin, but the beginning (1) and ending (6) is not showing. 


ggplot(dat, aes(x,y,color=z, label = round(z,2))) + geom_point() +
  scale_color_gradientn(
    colours = colors,
    values  = scales::rescale(c(1:6)),
    limit   = c(1,6),
    breaks  = c(1:7)-0.5, ###the label should be at 0.5,1.5,2.5,...,6.5
    labels  = my_breaks,
    guide = guide_colourbar(nbin = 6, raster = FALSE, frame.colour = "black", ticks.colour = NA,
                            direction = "horizontal", 
                            barwidth = 30, barheight = 2, label.hjust = 0)) + 
  geom_text() +
  theme(legend.position = 'bottom')

感谢您的帮助。

Answer 1

可能不是最优雅的，但请看以下内容。我还对您的点标签进行了一些调整。

fn scanl<T, F>(op: F, initial: T, list: &[T]) -> Vec<T>
where
    F: Fn(&T, &T) -> T,
{
    let mut acc = Vec::with_capacity(list.len());
    acc.push(initial);

    list.iter().fold(acc, |mut acc, val| {
        acc.push(op(val, acc.last().unwrap()));
        acc
    })
}
//scanl(|x, y| x + y, 0, &[1, 2, 3, 4, 5])

^{由reprex package（v0.3.0）于2019-06-14创建}