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label在ggplot的情节中写微米平方/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 * ")")