r语言 - 使用闪亮的输入、文本和希腊字母为 ggplot 添加标题

Question

我想在ggplot中添加以下标题：

"Number of times where UK emissions of Sulphur Dioxide exceeded 10 microgrammes per metre cubed"

此标题的组件来自：

free text = "Number of times where UK emissions of "
input$select = Sulphur Dioxide (or any other pollutant the user selects)
free text = "exceeded "
input$number = 10 (or any other integer the user selects)
formula = μg/m3 (where the 3 is superscript of m)

使用了粘贴和表达和引用的组合，但它只是不对。

这是我上面的代码....

ggplot() + 
aes(x=year, y=cnt) +
labs(title = paste("Number of times where UK emissions of ", input$select, 
" exceeded", input$number, expression(mu), "g/m", "^{3}"))

Answer 1

我不确定你在问什么，但如果你将"u03BCg/mu00B3"用于μg/m³部分，它会很好地打印。

Answer 2

或者如果你想使用正确的plotmath表达式，它看起来像这样

library(ggplot2)
ggplot(mtcars) + 
aes(x=mpg, y=disp) +
labs(title = bquote("Number of times where UK emissions of "~.(input$select)~ 
" exceeded"~.(input$number)~mu*g/m^3))