R help - Mar 2009 - using "substitute" inside a legend

Hello list,

I have a linear regression:

mylm = lm(y~x-1)

I've been reading old mail postings as well as the plotmath demo and I came
up with a way to print an equation resulting from a linear regression:

model = substitute(list("y"==slope%*%"x", R^2==rsq),
list(slope=round(mylm$coefficients[[1]],2),rsq=round(summary(mylm)$adj.r.squared,
2)))

I have four models and I need to list each equation in a legend. I'm using:

legend(20, 120, title = "fitted models", c(model1, model2, model3,
model4),
lty=1, col=c("blue", "red", "black",
"green"))

But this only works when I have up to two models. With four models the
formatting is lost. I suspect the concatenation converts the objects into
List and this destroys the formatting.

Does anybody have any suggestions? The main difficulty I have is
substituting R squared / slope values from a linear model into a
mathematical expression.

Thanks,

M.

	[[alternative HTML version deleted]]

Mathew Fox wrote:
> Hello list,
> 
> I have a linear regression:
> 
> mylm = lm(y~x-1)
> 
> I've been reading old mail postings as well as the plotmath demo and I
came
> up with a way to print an equation resulting from a linear regression:
> 
> model = substitute(list("y"==slope%*%"x", R^2==rsq),
>
list(slope=round(mylm$coefficients[[1]],2),rsq=round(summary(mylm)$adj.r.squared,
> 2)))
> 
> I have four models and I need to list each equation in a legend. I'm
using:
> 
> legend(20, 120, title = "fitted models", c(model1, model2,
model3, model4),
> lty=1, col=c("blue", "red", "black",
"green"))

legend(20, 120, title = "fitted models",
     do.call("expression", list(model1, model2, model3, model4)),
     lty=1, col=c("blue", "red", "black",
"green"))

Uwe Ligges

> But this only works when I have up to two models. With four models the
> formatting is lost. I suspect the concatenation converts the objects into
> List and this destroys the formatting.
> 
> Does anybody have any suggestions? The main difficulty I have is
> substituting R squared / slope values from a linear model into a
> mathematical expression.
> 
> Thanks,
> 
> M.
> 
> 	[[alternative HTML version deleted]]
> 
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