R - (ggplot) 使 geom_step 跳跃为虚线

我正在绘制离散 CDF。我有一些关于 geom_step 的问题，但我没有通过使用 Google 找到这些问题。

1. 是否可以将代表跳跃的线段做成虚线 而不是更扎实地更好地展示正在发生的事情？
2. 是否可以比我更有效地添加 geom_point ？ （较少的 c/p）。

以下是我当前的解决方案：

library(tidyverse)
library(ggthemes)
theme_set(theme_few())

x0 <- seq(-0.5, -0.01, by = 0.01)
x1 <- seq(0, 0.99, by = 0.02)
x2 <- seq(1, 1.99, by = 0.02)
x3 <- seq(2, 2.99, by = 0.02)
x35 <- seq(3, 3.49, by = 0.01)
x4 <- seq(3.5, 3.99, by = 0.01)

tibble_ex <- tibble(
  x0 = x0,
  x1 = x1,
  x2 = x2,
  x3 = x3,
  x35 = x35,
  x4 = x4
)

tibble_ex %>%
  gather(x, xax, x0:x4) %>%
  mutate(cdf = case_when(x == 'x0' ~ 0,
                         x == 'x1' ~ 1/2,
                         x == 'x2' ~ 3/5,
                         x == 'x3' ~ 4/5,
                         x == 'x35' ~ 9/10,
                         x == 'x4' ~ 1)) %>%
  ggplot(aes(x = xax, y = cdf)) +
  geom_step() +
  geom_point(aes(x = 0, y = 0), size = 3, shape = 21, fill = 'white') +
  geom_point(aes(x = 1, y = 0.5), size = 3, shape = 21, fill = 'white') +
  geom_point(aes(x = 2, y = 3/5), size = 3, shape = 21, fill = 'white') +
  geom_point(aes(x = 3, y = 4/5), size = 3, shape = 21, fill = 'white') +
  geom_point(aes(x = 3.5, y = 9/10), size = 3, shape = 21, fill = 'white') +
  geom_point(aes(x = 0, y = 0.5), size = 3, shape = 21, fill = 'black') +
  geom_point(aes(x = 1, y = 3/5), size = 3, shape = 21, fill = 'black') +
  geom_point(aes(x = 2, y = 4/5), size = 3, shape = 21, fill = 'black') +
  geom_point(aes(x = 3, y = 9/10), size = 3, shape = 21, fill = 'black') +
  geom_point(aes(x = 3.5, y = 1), size = 3, shape = 21, fill = 'black') +
  labs(x = 'x', y = 'F(x)')

如果您可以将数据放入数据框架中并对其进行结构化，以便可以直接映射数据的特征，那么 ggplot 的使用将会更加强大。

这是一种获取数据并通过将每个 x 与先前的 cdf 值匹配来用表示连接点的附加行来扩充数据的方法。我添加了一栏，type，以跟踪哪个是哪个。我也安排df以便geom_segment以正确的顺序绘制点。

new_steps <- 
  tibble(x = c(0:3, 3.5, 4),
         cdf = c(0, .5, .6, .8, .9, 1))


df <- new_steps %>%
  mutate(type = "cdf") %>%
  bind_rows(new_steps %>%
              mutate(type = "prior",
                     cdf = lag(cdf))) %>%
  drop_na() %>%
  arrange(x, desc(type))

然后我们可以绘制这些点'fill和 geom_segments 的线型为type.

ggplot(df) + 
  geom_point(aes(x, cdf, fill = type),
             shape = 21) +
  scale_fill_manual(values = c("black", "white")) +
  geom_segment(aes(x = lag(x), y = lag(cdf),
                   xend = x, yend = cdf,
                   lty = type)) +
  scale_linetype_manual(values = c("dashed", "solid"))