删除facet_wrap标签之间的水平线

如果您希望保留 theme_bw()，一种选择是创建一个新变量，将州和城市连接起来，并用换行符 (\n) 分隔：

df <- df %>%
  mutate(state_city = paste(state, city, sep = "\n\n"))

然后您可以使用新变量来显示图表：

df %>%
  ggplot(aes(x = year, y = value)) +
  geom_point() +
  theme_bw() +
  facet_wrap(~state_city)

因此完整的代码将是：

library(tidyverse)

set.seed(333)

# Example dataset
df <- data.frame(
  state = c("North Carolina","North Carolina","North Carolina",
            "North Carolina","North Carolina","North Carolina",
            "Virginia","Virginia","Virginia"),
  city = c("Boone","Boone","Boone",
           "Elizabeth City","Elizabeth City","Elizabeth City",
           "Norfolk","Norfolk","Norfolk"),
  year = rep(seq(2000,2004,2),3),
  value = round(rnorm(9,100,50))
)

#New variable
df <- df %>%
  mutate(state_city = paste(state, city, sep = "\n\n"))

# Example plot
df %>%
  ggplot(aes(x = year, y = value)) +
  geom_point() +
  theme_bw() +
  facet_wrap(~state_city)

有几种方法可以实现这一目标。更改主题，例如。到theme_light(A)，或修改条带背景和文本颜色 (B)。这些方法都不会修改数据。

df %>%
  ggplot(aes(x = year, y = value)) +
  geom_point() +
  theme_light() +
  facet_wrap(~state+city)

df %>%
  ggplot(aes(x = year, y = value)) +
  geom_point() +
  theme_bw() +
  facet_wrap(~state+city) +
  theme(strip.background=element_rect(color="grey90", fill="grey90"),
        strip.text=element_text(colour="black"))