如何用ggplot中的符号替换轴上的数字？

Question

我正在制作散点图，并想用符号替换 y 轴的数字。具体来说，我想将 20 替换为减号，将 0 替换为加号。

我看过this response，但我创建 y 轴的方式有点不同。

谢谢。

这是我的绘图代码：

library(tidyverse)

ggplot(exampledf, aes(x = male_diff, y = index, color = as.factor(expt_in_ms))) + 
  geom_point(aes(alpha = 0.5, size = 3)) +
  geom_point(aes(x = female_diff),alpha = 0.8, shape =24, size = 5) +
  scale_y_continuous(breaks = 1:nrow(exampledf), labels = exampledf$nloci) +
  xlab("difference in proportion") +
  ylab("correlation") +
  geom_vline(
    xintercept = 0,
    color = 'black',
    linetype = 'dashed',
    alpha = .5
  ) +
  theme_minimal() + theme(text = element_text(size = 12)) + guides(alpha=FALSE) + guides(size=FALSE) +
  guides(shape = FALSE) + guides(color = FALSE)

这是绘图代码中名为exampledf的数据集：

structure(list(male_diff = c(0.4668, -0.03299, 0.702, -0.11544, 
0.689, 0.511, -0.0725, -0.12844, -0.0827, 0.6515, -0.01077, 0.006, 
0.0041, -0.00856, 0.4181, -0.02765), female_diff = c(-0.459, 
0.022, -0.155, 0.00800000000000001, -0.156, -0.326, -0.0224, 
0.00700000000000001, 0.0399999999999999, 0.2182, -0.08458, 0.8844, 
-0.8459, 0.122, -0.506, 0.03), expt_in_ms = c(1, 1, 2, 2, 3, 
3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4), nloci = c(0, 20, 0, 20, 0, 
0, 0, 20, 20, 20, 0, 20, 0, 20, 0, 20), index = 1:16), row.names = c(NA, 
-16L), class = c("tbl_df", "tbl", "data.frame"))

Answer 1

您可以在 labels 参数中使用嵌套的 gsub()。在这里，\u2212 是 unicode 减号，但您也可以使用连字符。正则表达式位^ 表示“开始于”，而$ 表示“结束于”，所以^0$ 应该匹配精确的0。

library(tidyverse)

exampledf <- structure(
  list(male_diff = c(0.4668, -0.03299, 0.702, -0.11544, 0.689, 0.511, -0.0725, 
                     -0.12844, -0.0827, 0.6515, -0.01077, 0.006, 0.0041, 
                     -0.00856, 0.4181, -0.02765), 
       female_diff = c(-0.459, 0.022, -0.155, 0.00800000000000001, -0.156, 
                       -0.326, -0.0224, 0.00700000000000001, 0.0399999999999999,
                       0.2182, -0.08458, 0.8844, -0.8459, 0.122, -0.506, 0.03), 
       expt_in_ms = c(1, 1, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4), 
       nloci = c(0, 20, 0, 20, 0, 0, 0, 20, 20, 20, 0, 20, 0, 20, 0, 20), 
       index = 1:16), 
  row.names = c(NA, -16L), class = c("tbl_df", "tbl", "data.frame")
)

ggplot(exampledf, aes(x = male_diff, y = index, color = as.factor(expt_in_ms))) + 
  geom_point(aes(alpha = 0.5, size = 3)) +
  geom_point(aes(x = female_diff),alpha = 0.8, shape =24, size = 5) +
  scale_y_continuous(
    breaks = 1:nrow(exampledf), 
    labels = gsub("^0$", "+", gsub("^20$", "\u2212", exampledf$nloci))
  ) +
  xlab("difference in proportion") +
  ylab("correlation") +
  geom_vline(
    xintercept = 0,
    color = 'black',
    linetype = 'dashed',
    alpha = .5
  ) +
  theme_minimal() + 
  theme(text = element_text(size = 12)) + 
  guides(alpha="none", size = "none", shape = "none", color = "none")

^{由reprex package (v1.0.0) 于 2021 年 8 月 31 日创建}