R help - Feb 2005 - QCC and PlotMath question

For some reason, using the qcc package, I'm unable to use the plotmath
notation in the title.  Can anyone see what I'm doing wrong?

library(qcc)
a <- rnorm(100)
qcc(a,type="xbar.one",title=expression(bar(X)),ylab=expression(CFU/ft^3)
)

This seems to not let the expression be evaluated, so I tried:

qcc(a,type="xbar.one",title=eval(expression(bar(X))),ylab=expression(CFU
/ft^3))

And get the following error:
Error in eval(expr, envir, enclos) : couldn't find function "bar"

Any thoughts?

-----------------------------------------------------------------
"Policies are many, Principles are few, Policies will change, Principles
never do." 
-John C. Maxwell


Shawn Way, PE

Shawn Way wrote:
> For some reason, using the qcc package, I'm unable to use the plotmath
> notation in the title.  Can anyone see what I'm doing wrong?
> 
> library(qcc)
> a <- rnorm(100)
>
qcc(a,type="xbar.one",title=expression(bar(X)),ylab=expression(CFU/ft^3)
> )
> 
> This seems to not let the expression be evaluated, so I tried:
> 
>
qcc(a,type="xbar.one",title=eval(expression(bar(X))),ylab=expression(CFU
> /ft^3))
> 
> And get the following error:
> Error in eval(expr, envir, enclos) : couldn't find function
"bar"
> 
> Any thoughts?
Add the title by a separate call:

   qcc(a, type="xbar.one", title="",
ylab=expression(CFU/ft^3))
   title(expression(bar(X)))

Uwe Ligges
> -----------------------------------------------------------------
> "Policies are many, Principles are few, Policies will change,
Principles
> never do." 
> -John C. Maxwell
> 
> 
> Shawn Way, PE
> 
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