R help - Apr 2011 - How to paste a vector of expressions and a character vector?

Dear expeRts,

I know I can't paste expressions in the normal way, but I just couldn't
figure out
how to get the following (I want to paste a character vector to an expression
vector)
right with bquote() or substitute.

vec1 <- c("a", expression(tilde(b)), "c")
vec2 <- c("1", "2", "3")
main <- as.expression(paste(vec1, vec2))
plot(0,0, main=main[2])

Cheers,

Marius

On Apr 1, 2011, at 12:32 PM, Marius Hofert wrote:
> Dear expeRts,
>
> I know I can't paste expressions in the normal way, but I just  
> couldn't figure out
> how to get the following (I want to paste a character vector to an  
> expression vector)
> right with bquote() or substitute.
>
> vec1 <- c("a", expression(tilde(b)), "c")
> vec2 <- c("1", "2", "3")
> main <- as.expression(paste(vec1, vec2))
> plot(0,0, main=main[2])
Do not use `paste` ... it coerces your expression to a character  
value ... use `c` instead:

 > main <- as.expression(c(vec1, vec2))
 > plot(1,1, main=main[2])

And then, even the as.expression is superfluous:

 > main <- c(vec1, vec2)
 > plot(1,1, main=main[2])

-- 

David Winsemius, MD
West Hartford, CT