r - 如何用 ggplot2 绘制长图例

Question

我想在图表底部绘制多折线图的长图例。如果不使用较小的图例字体，我该如何做到这一点？以下示例使用 6 条线，但我也使用了更多线的图形。

library(tidyverse)
df <- tibble(d = c(1,1,2,2,3,3,4,4,5,5,6,6),
             name = c("long long long long long text 1",
                      "long long long long long text 1",
                      "long long long long long text 2",
                      "long long long long long text 2",
                      "long long long long long text 3",
                      "long long long long long text 3",
                      "long long long long long text 4",
                      "long long long long long text 4",
                      "long long long long long text 5",
                      "long long long long long text 5",
                      "long long long long long text 6",
                      "long long long long long text 6"),
             year = c(2010, 2011, 2010, 2011, 2010, 2011, 2010, 2011,
                      2010, 2011, 2010, 2011),
             value = c(0.1,0.2,0.3,0.4,0.5,0.6,0.6,0.5,0.4,0.3,0.2,0.1))

ggplot(data = df, aes(x = year, y = value)) +
  geom_line(aes(color = name, linetype = name), size = 1) +
  geom_point(aes(shape = name, color = name), size = 2) +
  theme_bw() +
  theme(axis.text.x=element_text(size=rel(1.5), angle=90),
        axis.text.y=element_text(size=rel(1.5)),
        legend.title=element_blank(),
        legend.text=element_text(size=rel(1.5)),
        legend.position = "bottom",
        axis.line = element_line(color = 'black'),
        panel.border = element_blank(),
        panel.background = element_blank(),
        panel.grid.major.x = element_blank(),
        panel.grid.minor.x = element_blank()) +
  scale_x_continuous(breaks=seq(2010, 2011, by = 1)) +
  labs(
    title = "Chart title",
    x = NULL,
    y = "No."
  ) +
  ylim(0, 1)

标签： rggplot2

Answer 1

guide使用函数控制行数或列数：

p + scale_color_discrete(guide = guide_legend(ncol = 1))

p上面的绘图代码在哪里。