如何在R中的绘图标签中书写微米平方米

Question

我想在ggplot中的绘图label中写入微米平方米/立方米，在添加m^2时出错。第一个表达式可以，但缺少^2。我添加m^2的尝试没有成功，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="")))

感谢

Answer 1

这只是一个报价问题：

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，更短：

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