[R] How do one modify an expression?

[Uwe Ligges]

Henrik Bengtsson wrote:
> 
> I am using expressions to annotate x and y labels in plots. I start of with
> a label as
> 
>   xlab <- expression(X)
> 
> Note that it is the user that sets this. It could also be something more
> complicated as expression(sqrt(R*G)). Can I easily add a log[2] "around"
> this expression? I would like to get
> 
>   xlab <- expression(log[2](X))
> 
> I basically know nothing about expressions.

The following seems to work:

  plot(1:10, xlab= expression(log[2](X))) 

So I don't understand your question. For help on plot annotation have a
look at:

  ?plotmath


Uwe Ligges
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