strip.position external in 两列 facet_wrap 图

Posted 2023-02-16

【中文标题】strip.position external in 两列 facet_wrap 图

【英文标题】：strip.position external in two columns facet_wrap plot

【发布时间】：2021-12-07 07:28:24

【问题描述】：

在两列 facet_wrap 图形中，将 facet 的名称和轴放在左侧用于左列，在右侧用于右列，这样会更方便和更好，以便获得紧凑的绘图，刻面靠得很近。

ggplot(economics_long, aes(date, value)) +
  geom_line() +
  labs(y="") +
  facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "left") +
       theme(strip.background = element_blank(), strip.placement = "outside")

【参考方案1】：

据我所知，在香草 ggplot2 中没有办法做到这一点。如果您对 gtables 感到满意，您可能会发现以下方法可行。

library(ggplot2)

# Base plot
p <- ggplot(economics_long, aes(date, value)) +
  geom_line() +
  labs(y="") +
  theme(strip.background = element_blank(), strip.placement = "outside")

# Left aligned strips/axes
left <- p +
  facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "left")

# Right aligned strips/axes
right <- p +
  facet_wrap(~variable, scales = "free_y", ncol = 2, strip.position = "right") +
  scale_y_continuous(position = "right")

# Convert to gtables
left  <- ggplotGrob(left)
right <- ggplotGrob(right)

# Combine parts of left and right
# Column numbers found by browsing through layout
gt <- cbind(left[, 1:7], right[, 9:ncol(right)])

# Render
grid::grid.newpage(); grid::grid.draw(gt)

^{由reprex package (v2.0.1) 于 2021-10-20 创建}

要以编程方式而不是手动判断表格布局来查找面板位置，我最好的猜测是这样做：

panels_left  <- panel_cols(left)$l
panels_right <- panel_cols(right)$l

# The -2 is to include the left axis space (zero width because of absence) 
# and the panel spacing
gt <- cbind(left[, 1:panels_left[1]],
            right[, (panels_right[2]-2):ncol(right)])
grid::grid.newpage(); grid::grid.draw(gt)