如何在R中的标绘标签中写出每立方米的微米平方

Question

我想在ggplot中的情节label中写微米平方/立方米，当我添加m ^ 2时出现错误。第一个表达式还可以，但它缺少^ 2。我尝试添加m ^ 2不起作用，因为我没有看到上标。

1. ylab (expression(paste("Surface area concentration (",mu,"m/",m^3,")", sep="")))

2. ylab (expression(paste("Surface area concentration (",mu,",m^2,"/,m^3,")", sep="")))

谢谢

Answer 1

这只是一个引用问题：

library(ggplot2)
qplot(mpg, wt, data = mtcars) + 
ylab (expression(paste(
  "Surface area concentration (",
  mu, m^2, "/", m^3,
  ")", sep="")))

Answer 2

试试这个：

 qplot(0, ylab = ~ "Surface area concentration ( " * mu * m^2 / m^3 * ")")

Answer 3

或者，甚至更短：

plot(0, ylab = ~ "Surface area concentration" (mu * m^2 / m^3))
plot(0, ylab = Surface~area~concentration (mu * m^2 / m^3))