On Thu, Apr 4, 2013 at 4:39 AM, Shane Carey <careys...@gmail.com> wrote:
> Hi William,
>
> for (i in one:length(DATA_names))
> if ((grepl("_",DATA_names[i]))=="TRUE")
> DATA_names[i]<-f(DATA_names[i]))
>
> I keep getting an error saying: incompatible types (from symbol to
> character) in subassignment type fix
>
>
I would urge you not to obliterate DATA_names by writing on top of itself.
That creates bugs that are really tough to solve.
Remember that a character variable is not the same thing as an expression.
I mean, an expression is generally a list structure, not interchangeable
with a character string. If that f() function is creating expressions, and
you are trying to obliterate a character vector with expressions, you will
get errors, as you have seen.
I'm pretty sure that to catch the results of a function that creates
expressions, your receiver object has to be a list. My first try would be
myList <- vector("list", length(DATA_names))
for (i in one:length(DATA_names))
if ((grepl("_", DATA_names[i])) == "TRUE")
myList[[i]] <- f(DATA_names[i]))
I copied your code to my system and found I couldn't run it because you had
one more paren than was needed and the word "one" was undefined. But after
fixing that, here's evidence my way works:
Note I inserted some spaces in your code, since it is inhumane to smash
together all those letters around a poor little <- :).
DATA_names<-c("A_mgkg","B_mgkg","C_mgkg","D_mgkg","E_mgkg","F_mgkg","G_mgkg","H
mgkg")
f <- function (name)
{
# add other suffices and their corresponding plotmath expressions to the
list
env <- list2env(list(mgkg = bquote(mg ~ kg^{-1}),
ugkg = bquote(mu * g ~ kg^{-1})),
parent = emptyenv())
pattern <- paste0("_(", paste(objects(env), collapse="|"), ")")
bquoteExpr <- parse(text=gsub(pattern,
"~(.(\\1))",
name))[[1]]
## I use do.call() to work around the fact that bquote's first argument is
## not evaluated.
do.call(bquote, list(bquoteExpr, env))
}
myList <- vector("list", length(DATA_names))
for (i in 1:length(DATA_names))
if ((grepl("_", DATA_names[i])) == "TRUE")
myList[[i]] <- f(DATA_names[i])
myList
> myList
[[1]]
A ~ (mg ~ kg^{
-1
})
[[2]]
B ~ (mg ~ kg^{
-1
})
[[3]]
C ~ (mg ~ kg^{
-1
})
[[4]]
D ~ (mg ~ kg^{
-1
})
[[5]]
E ~ (mg ~ kg^{
-1
})
[[6]]
F ~ (mg ~ kg^{
-1
})
[[7]]
G ~ (mg ~ kg^{
-1
})
[[8]]
NULL
I asked a very similar question here last year and got many interesting
suggestions. I was so fascinated I wrote a little programming vignette
called Rchaeology in my package "rockchalk". As soon as you settle on the
most direct route from start to end, please post, I might learn new tricks.
In your case, I've been wondering if you ought to edit the string before it
becomes an expression, or whether you should edit the expression after. I
needed a correct expression to start, though. This writes the correct
thing in the middle of the graph. Correct?
xcorrect <- expression(X ~~ "mg kg"^{-1})
plot(1:10, 1:10, type ="n")
text(5, 5, xcorrect)
Supposing that's correct, watch this.
mgkg <- quote("mg kg"^{-1})
text(4, 2, bquote(A ~~ .(mgkg)))
text(4, 3, bquote(B ~~ .(mgkg)))
text(4, 6, bquote(C ~~ .(mgkg)))
I've got the "units" captured in mgkg, and then when I want to draw that
into
and expression, i used bquote. substitute works as well, maybe more clear.
text(3, 8, substitute(B ~~ myUnit, list(myUnit = mgkg)))
In any case, I thought this was a fun question.
pj
> Have you any ideas on how to get around this, thanks again for your help,
> much appreciated.
> Cheers
>
>
> On Wed, Apr 3, 2013 at 5:33 PM, William Dunlap <wdun...@tibco.com> wrote:
>
> > Are you trying to convert a column name like "Na_mgkg" to a plot label
> > like Na (mg kg^-1) ?
> > If so you will have to use both string manipulation functions like gsub()
> > and expression manipulating
> > functions like bquote(). E.g.,
> >
> > f <- function (name)
> > {
> > # add other suffices and their corresponding plotmath expressions to
> > the list
> > env <- list2env(list(mgkg = bquote(mg ~ kg^{-1}),
> > ugkg = bquote(mu * g ~ kg^{-1})),
> > parent = emptyenv())
> > pattern <- paste0("_(", paste(objects(env), collapse="|"), ")")
> > bquoteExpr <- parse(text=gsub(pattern,
> > "~(.(\\1))",
> > name))[[1]]
> > # I use do.call() to work around the fact that bquote's first argument
> > is not evaluated.
> > do.call(bquote, list(bquoteExpr, env))
> > }
> >
> > d <- data.frame("Na_mgkg"=1:10, "K_ugkg"=10:1)
> > plot(Na_mgkg ~ K_ugkg, data=d, xlab=f("K_ugkg"), ylab=f("Na_mgkg"))
> >
> > Bill Dunlap
> > Spotfire, TIBCO Software
> > wdunlap tibco.com
> >
> >
> > > -----Original Message-----
> > > From: r-help-boun...@r-project.org [mailto:
> r-help-boun...@r-project.org]
> > On Behalf
> > > Of Shane Carey
> > > Sent: Wednesday, April 03, 2013 8:02 AM
> > > To: r-help@r-project.org
> > > Subject: [R] Superscript
> > >
> > > Hi,
> > > How do I write a superscript within gsub?
> > >
> > > I have the following: gsub("_mgkg",expression(paste("mg
> > kg"^{-1})),names[1])
> > >
> > > Thanks
> > >
> > >
> > >
> > > --
> > > Shane
> > >
> > > [[alternative HTML version deleted]]
> > >
> > > ______________________________________________
> > > R-help@r-project.org mailing list
> > > https://stat.ethz.ch/mailman/listinfo/r-help
> > > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html
> > > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> --
> Shane
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Paul E. Johnson
Professor, Political Science Assoc. Director
1541 Lilac Lane, Room 504 Center for Research Methods
University of Kansas University of Kansas
http://pj.freefaculty.org http://quant.ku.edu
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