删除 ggplot2 的 x 轴标签？

Question

给出以下数据：

    data2 <- list(structure(list(super_group = c(1,1), Group.1 = structure(3:4, .Label = c("A","B", "C", "D", "E", "F"), class = "factor"), Pr1 = c(65, 75), Pr2 = c(54, 88), Prh = c(25, 5), SE = c(25, 75 )), row.names = c(NA, -2L), class = "data.frame"), NULL, structure(list(super_group = c(3,3), Group.1 = structure(3:4, .Label = c("A","B", "C", "D", "E", "F"), class = "factor"), Pr1 = c(81,4), Pr2 = c(66, 57),Prh = c(3,3), SE = c(8, 9)), row.names = c(NA,
-2L), class = "data.frame"))

使用 ggplot2 绘图：

 data2 %>%
 bind_rows() %>%
 ggplot(., aes(x = Group.1, y = Pr1, fill = Group.1)) +
 geom_bar(stat = "identity") +
 facet_grid(. ~ super_group)

-您在 x 轴上看到 C 和 D 标签，这是不必要的。所以我想删除它们并减小条的宽度。有什么想法吗？

-我们可以将 1 和 3 从 x 轴顶部移动到 x 轴底部吗？

Answer 1

我们可以使用switch 参数到facet_grid 来更改构面标签的位置。
参数axis.text.x 和axis.ticks.x 控制文本并在x 轴上打勾。要删除它们，请将它们声明为 element_blank()。

library(tidyverse)
data2 %>%
  bind_rows() %>%
  ggplot(., aes(x = Group.1, y = Pr1, fill = Group.1)) +
  geom_bar(stat = "identity") +
  facet_grid(. ~ super_group, switch = "x") +
  theme(axis.text.x = element_blank(),
        axis.ticks.x = element_blank()) -> p1

要更改图形的比例，请以不同的尺寸保存它。示例：

ggsave("p1.pdf", plot = p1, device = "pdf", width = 3, height = 5)

或者如果使用knitr，通过定义更改块选项：

fig.width=3, fig.height=5 例如：

```{r p1, fig.width=3, fig.height=5}  
data2 %>%
      bind_rows() %>%
      ggplot(., aes(x = Group.1, y = Pr1, fill = Group.1)) +
      geom_bar(stat = "identity") +
      facet_grid(. ~ super_group, switch = "x") +
      theme(axis.text.x = element_blank(),
            axis.ticks.x = element_blank())
``` 

并使用参数width更改条的宽度：

data2 %>%
  bind_rows() %>%
  ggplot(., aes(x = Group.1, y = Pr1, fill = Group.1)) +
  geom_bar(stat = "identity", width = 0.5) +
  facet_grid(. ~ super_group, switch = "x") +
  theme(axis.text.x = element_blank(),
        axis.ticks.x = element_blank())

另一种选择（基于 cmets 在我看来这是想要的）是更改 expand:

data2 %>%
  bind_rows() %>%
  ggplot(., aes(x = Group.1, y = Pr1, fill = Group.1)) +
  geom_bar(stat = "identity") +
  facet_grid(. ~ super_group, switch = "x") +
  scale_x_discrete(expand = c(1,1))+
  theme(axis.text.x = element_blank(),
        axis.ticks.x = element_blank())