ggplot:分组条形图中x轴上的刻度和标签的不同位置

Question

我准备了一个MWE,希望能帮助我们在x轴的不同位置设置刻度和标签,以获得分组条形图.

library(ggplot2)
library(reshape2)

data <- data.frame(name = c("X","Y","Z"), A = c(2,4,6), B = c(1,3,4), C = c(3,4,5))
data <- melt(data, id = 1)

ggplot(data, aes(name,value)) +
  geom_bar(aes(fill = variable), position = "dodge", stat = "identity")

刻度应显示在组之间,但标签位于分组条形下方(如图中所示).我尝试设置用户定义的中断(作为因子),scale_x_discrete但它只使我的刻度和标签完全消失.

任何帮助深表感谢!

Answer 1

一种选择是将离散x标度转换为连续标度,以便于计算break位置:

# numeric version of x values
data$x <- as.integer(as.factor(data$name))

1.组之间的x刻度

x_tick <- head(unique(data$x), -1) + 0.5
len <- length(x_tick)

ggplot(data, aes(x = x, y = value, fill = variable)) + 
  geom_col(position = "dodge") +
  scale_x_continuous(breaks = c(sort(unique(data$x)), x_tick),
                     labels = c(sort(unique(data$name)), rep(c(""), len))) +
  theme(axis.ticks.x = element_line(color = c(rep(NA, len + 1), rep("black", len))))

2:x在小组组之前,之间和之后打勾

x_tick <- c(0, unique(data$x)) + 0.5
len <- length(x_tick)

ggplot(data, aes(x = x, y = value, fill = variable)) + 
  geom_col(position = "dodge") +
  scale_x_continuous(breaks = c(sort(unique(data$x)), x_tick),
                     labels = c(sort(unique(data$name)), rep(c(""), len))) +
  theme(axis.ticks.x = element_line(color = c(rep(NA, len - 1), rep("black", len))))

不要问我有关分别出现在2.25和1.75的额外网格线...