如何使用grid.arrange实现零间距拼接镜像ggplot柱状图

你可以通过调整图表边距+使用patchwork拼接包的方式实现需求，最终支持PlotLR <- PL + PR的调用形式，完整可运行代码如下：

# 加载必要包
library(ggplot2)
library(patchwork)

# 原始数据
DWP1 <- data.frame("City" = c("Berlin", "Paris", "London"),
                   "People" = c(3.3, 2.1, 9))
DWP2 <- data.frame("City" = c("New York", "Washington", "Miami"),
                  "People" = c(8.4, 0.7, 0.4))
# 定义字体变量（匹配原代码引用的Schriftart，可替换为你实际使用的字体）
Schriftart <- "sans"

# 右侧图PR
PR <- ggplot(DWP1, aes(x = reorder(City, People), y = People))+
  geom_col(aes(fill = City), width = 0.1, position =  position_dodge(-0.9), linetype="dotted")+
  coord_flip()+
  scale_y_continuous(expand = expansion(mult = c(0, .1)), limits = c(0, 10)) + # 固定y轴范围保证对齐
  theme(
    axis.line = element_line(),
    panel.background = element_rect(fill = "transparent", color = NA),
    plot.background = element_rect(fill= "transparent", color = NA),
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    panel.border = element_blank(),
    legend.position = "none",
    axis.title = element_blank(),
    axis.text = element_blank(),
    axis.ticks = element_blank(),
    axis.line.x = element_blank(),
    # 核心修改：左侧边距设为0，消除和左图的空隙
    plot.margin = unit(c(0,5,0,0), "pt")
  )

# 左侧图PL
PL <- ggplot(DWP2, aes(x = reorder(City, People), y = People))+
  geom_col(aes(fill = City), width = 0.1)+
  coord_flip()+
  # 合并scale_y配置，避免重复定义冲突，同时固定y轴范围
  scale_y_reverse(expand = expansion(mult = c(0, .1)), limits = c(10, 0)) +
  theme(
    axis.line = element_line(),
    panel.background = element_rect(fill = "transparent", color = NA),
    plot.background = element_rect(fill= "transparent", color = NA),
    panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    panel.border = element_blank(),
    legend.position = "none",
    axis.title = element_blank(),
    axis.text = element_blank(),
    axis.ticks = element_blank(),
    axis.line.x = element_blank(),
    axis.line.y = element_blank(),
    # 核心修改：右侧边距设为0，消除和右图的空隙
    plot.margin = unit(c(0,0,0,5), "pt")
  )

# 直接用加号拼接，生成最终对象PlotLR
PlotLR <- PL + PR + plot_layout(nrow = 1)

关键修改说明 #

• 消除了原代码中scale_y_continuous和scale_y_reverse重复定义的冲突，将expand参数统一写入scale_y_reverse
• 新增plot.margin配置，将左图右侧、右图左侧的边距设为0，彻底消除两张图拼接处的空隙
• 固定两张图的y轴范围，保证拼接后柱体高度对齐
• 使用patchwork包实现你需要的PL + PR语法拼接，plot_layout默认无额外间距，符合无缝拼接需求

内容的提问来源于stack exchange，提问作者Alex_