I can't find a way how to write subscripts in the title or the subtitle in R. How can I write v 1,2 with 1,2 as subscripts?
Thanks for your help!
expression is your friend:
plot(1,1, main=expression('title'^2)) #superscript
plot(1,1, main=expression('title'[2])) #subscript
If you are looking to have multiple subscripts in one text then use the star(*) to separate the sections:
plot(1:10, xlab=expression('hi'[5]*'there'[6]^8*'you'[2]))
See ?expression
plot(1:10,main=expression("This is a subscript "[2]))
A subscript and referring to a stored value...
a <- 10
plot(c(0,1), c(0,1), type = 'n', ann = FALSE, xaxt = 'n', yaxt = 'n')
text(0.2, 0.6, cex = 1.5, bquote(paste('S'['f']*' = ', .(a))))
Another example, expression works for negative superscripts without the need for quotes around the negative number:
title(xlab=expression("Nitrate Loading in kg ha"^-1*"yr"^-1))
and you only need the * to separate sections as mentioned above (when you write a superscript or subscript and need to add more text to the expression after).
As other users have pointed out, we use expression(). I'd like to answer the original question which involves a comma in the subscript:
How can I write v 1,2 with 1,2 as subscripts?
plot(1:10, 11:20 , main=expression(v["1,2"]))
Also, I'd like to add the reference for those looking to find the full expression syntax in R plotting: For more information see the ?plotmath help page. Running demo(plotmath) will showcase many expressions and relevant syntax.
Remember to use * to join different types of text within an expression.
Here is some of the sample output from demo(plotmath):
来源：https://stackoverflow.com/questions/10156417/subscripts-in-plots-in-r