如何在ggplot2中修改森林图特定分组的线条颜色

你可以通过scale_color_manual()函数手动指定各分组的颜色，精准设置Treatment A为亮橙色、Treatment B为淡紫色/薰衣草色。以下是修改后的完整代码：

tester <- data.frame(
  treatmentgroup = c("TreatmentA", "TreatmentB", "TreatmentC", "TreatmentD", "TreatmentE", "TreatmentF", "TreatmentA", "TreatmentB", "TreatmentC", "TreatmentD", "TreatmentE", "TreatmentF"),
  rr = c(1.12, 1.9, 1.05, 0.76, 1.5, 1.11, 1.67, 0.78, 2.89, 3.2, 1.33, 1.29),
  low_ci = c(0.71, 0.76, 0.78, 0.48, 0.91, 0.73, 1, 0.34, 0.75, 1, 1.18, 0.18),
  up_ci = c(1.6, 1.7, 2.11, 1.4, 1.5, 1.7, 2.6, 3.1, 9.3, 9.4, 1.9, 2),
  RR_ci = c(
    "1.12 (0.71, 1.6)", "1.9 (0.76, 1.7)", "1.05 (0.78, 2.1)", "0.76 (0.48, 1.4)", "1.5 (0.91, 1.5)", "1.11 (0.73, 1.7)",
    "1.67 (1, 2.6)", "0.78 (0.34, 3.1)", "2.89 (0.75, 9.3)", "3.2 (1, 9.4)", "1.33 (1.18, 1.9)", "1.29 (0.18, 2)"
  ),
  ci = c(
    "0.71, 1.6",
    "0.76, 1.7",
    "0.78, 2.1",
    "0.48, 1.4",
    "0.91, 1.5",
    "0.73, 1.7",
    "1, 2.6",
    "0.34, 3.1",
    "0.75, 9.3",
    "1, 9.4",
    "1.18, 1.9",
    "0.18, 2"
  ),
  X = c("COPD", "COPD", "COPD", "COPD", "COPD", "COPD", "Cancer", "Cancer", "Cancer", "Cancer", "Cancer", "Cancer"),
  no = c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
)


# 降低网格线透明度：默认值为255
col_grid <- rgb(235, 235, 235, 100, maxColorValue = 255)

library(dplyr, warn = FALSE)
library(ggplot2)
library(patchwork)

forest <- ggplot(
  data = tester,
  aes(x = treatmentgroup, y = rr, ymin = low_ci, ymax = up_ci)
) +
  geom_pointrange(aes(col = treatmentgroup)) +
  geom_hline(yintercept = 1, colour = "red") +
  xlab("Treatment") +
  ylab("RR (95% Confidence Interval)") +
  geom_errorbar(aes(ymin = low_ci, ymax = up_ci, col = treatmentgroup), width = 0, cex = 1) +
  facet_wrap(~X, strip.position = "top", nrow = 9, scales = "free_y") +
  theme_classic() +
  # 新增手动颜色映射
  scale_color_manual(
    values = c(
      "TreatmentA" = "#FF7F24", # 亮橙色
      "TreatmentB" = "#9370DB", # 淡紫色/薰衣草色
      "TreatmentC" = "#696969", # 其余分组用灰色
      "TreatmentD" = "#696969",
      "TreatmentE" = "#696969",
      "TreatmentF" = "#696969"
    )
  ) +
  theme(
    panel.background = element_blank(), strip.background = element_rect(colour = NA, fill = NA),
    strip.text.y = element_text(face = "bold", size = 12),
    panel.grid.major.y = element_line(colour = col_grid, size = 0.5),
    strip.text = element_text(face = "bold"),
    panel.border = element_rect(fill = NA, color = "black"),
    legend.position = "none",
    axis.text = element_text(face = "bold"),
    axis.title = element_text(face = "bold"),
    plot.title = element_text(face = "bold", hjust = 0.5, size = 13)
  ) +
  coord_flip()

dat_table <- tester %>%
  select(treatmentgroup, X, RR_ci, rr) %>%
  mutate(rr = sprintf("%0.1f", round(rr, digits = 1))) %>%
  tidyr::pivot_longer(c(rr, RR_ci), names_to = "stat") %>%
  mutate(stat = factor(stat, levels = c("rr", "RR_ci")))

table_base <- ggplot(dat_table, aes(stat, treatmentgroup, label = value)) +
  geom_text(size = 3) +
  scale_x_discrete(position = "top", labels = c("rr", "95% CI")) +
  facet_wrap(~X, strip.position = "top", ncol = 1, scales = "free_y", labeller = labeller(X = c(Cancer = "", COPD = ""))) +
  labs(y = NULL, x = NULL) +
  theme_classic() +
  theme(
    strip.background = element_blank(),
    panel.grid.major = element_blank(),
    panel.border = element_blank(),
    axis.line = element_blank(),
    axis.text.y = element_blank(),
    axis.text.x = element_text(size = 12),
    axis.ticks = element_blank(),
    axis.title = element_text(face = "bold"),
  )

forest + table_base + plot_layout(widths = c(10, 4))

关键说明 #

scale_color_manual()的values参数接受一个命名向量，键是分组名称，值是对应的颜色代码：

• 亮橙色用#FF7F24（可根据需求替换为#FFA500等其他亮橙色系代码）
• 淡紫色/薰衣草色用#9370DB（也可替换为#E6E6FA这类更浅的薰衣草色）
• 其余分组统一设置为灰色#696969，你也可以单独为每个分组指定不同颜色。

内容的提问来源于stack exchange，提问作者Roaring