Dear all,
I'm looking to create a formula within a function to pass to glmer()
and I'm having a problem that the following example will illustrate:
library(lme4)
y1 = rnorm(10)
x1 = data.frame(x11=rnorm(10), x12=rnorm(10), x13=rnorm(10))
x1 = data.matrix(x1)
w1 = data.frame(w11=sample(1:3,10, replace=TRUE), w12=sample(1:3,10,
replace=TRUE), w13=sample(1:3,10, replace=TRUE))
test1 <- function(x2, y2, w2) {
print(str(w2))
form = as.formula(paste("y2 ~ x2 +" ,paste("(1|w2$",
names(w2), ")",
collapse=" + ", sep="")))
m1 = glmer(form)
return(m1)
}
model1 = test1(x2=x1, y2=y1, w2=w1)
As can be seen from the print statement within the function, the
object "w2" is present and is a data frame. However, the following
error occurs:
Error in is.factor(x) : object 'w2' not found
This can be rectified by making 'w2' global - defining it outside the
function. I know there are issues with defining formulas and
environment but I'm not sure why this problem is specific to 'w2'
and
not the other objects passed to the function.
Any help would be appreciated.
Aidan MacNamara
EMBL-EBI
Hello,
Try the following. It uses argument 'data' to pass the data.frame w2. In
the function below, I've changed the pastes to two lines of code because
the first one changes the way the formula is put together.
test1 <- function(x2, y2, w2) {
#print(str(w2))
p1 <- paste("(1|", names(w2), ")", collapse=" +
", sep="")
p2 <- paste("y2 ~ x2 +" , p1)
form = as.formula(p2)
m1 = glmer(form, data = w2)
return(m1)
}
Hope this helps,
Rui Barradas
Em 09-01-2013 16:53, Aidan MacNamara escreveu:> Dear all,
>
> I'm looking to create a formula within a function to pass to glmer()
> and I'm having a problem that the following example will illustrate:
>
> library(lme4)
> y1 = rnorm(10)
> x1 = data.frame(x11=rnorm(10), x12=rnorm(10), x13=rnorm(10))
> x1 = data.matrix(x1)
> w1 = data.frame(w11=sample(1:3,10, replace=TRUE), w12=sample(1:3,10,
> replace=TRUE), w13=sample(1:3,10, replace=TRUE))
>
> test1 <- function(x2, y2, w2) {
>
> print(str(w2))
> form = as.formula(paste("y2 ~ x2 +" ,paste("(1|w2$",
names(w2), ")",
> collapse=" + ", sep="")))
> m1 = glmer(form)
> return(m1)
> }
>
> model1 = test1(x2=x1, y2=y1, w2=w1)
>
> As can be seen from the print statement within the function, the
> object "w2" is present and is a data frame. However, the
following
> error occurs:
>
> Error in is.factor(x) : object 'w2' not found
>
> This can be rectified by making 'w2' global - defining it outside
the
> function. I know there are issues with defining formulas and
> environment but I'm not sure why this problem is specific to
'w2' and
> not the other objects passed to the function.
>
> Any help would be appreciated.
>
> Aidan MacNamara
> EMBL-EBI
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
On Jan 9, 2013, at 8:53 AM, Aidan MacNamara wrote:> Dear all, > > I'm looking to create a formula within a function to pass to glmer() > and I'm having a problem that the following example will illustrate: > > library(lme4) > y1 = rnorm(10) > x1 = data.frame(x11=rnorm(10), x12=rnorm(10), x13=rnorm(10)) > x1 = data.matrix(x1) > w1 = data.frame(w11=sample(1:3,10, replace=TRUE), w12=sample(1:3,10, > replace=TRUE), w13=sample(1:3,10, replace=TRUE)) > > test1 <- function(x2, y2, w2) { > > print(str(w2)) > form = as.formula(paste("y2 ~ x2 +" ,paste("(1|w2$", names(w2), ")", > collapse=" + ", sep=""))) > m1 = glmer(form) > return(m1) > } > > model1 = test1(x2=x1, y2=y1, w2=w1) > > As can be seen from the print statement within the function, the > object "w2" is present and is a data frame. However, the following > error occurs: > > Error in is.factor(x) : object 'w2' not foundGenerally regression functions in R will be expecting to get one 'data' argument and build formulas using column names from that object. test1 <- function(x2, y2, w2) { w3 <- cbind(w2, x2, x2) print(str(w3)) form = as.formula(paste("y2 ~ x2 +" ,paste("(1|", names(w2), ")", collapse=" + ", sep=""))) m1 = glmer(form, data=w3); print(summary(m1)) return(m1) } model1 = test1(x2=x1, y2=y1, w2=w1)> > This can be rectified by making 'w2' global - defining it outside the > function. I know there are issues with defining formulas and > environment but I'm not sure why this problem is specific to 'w2' and > not the other objects passed to the function. > > Any help would be appreciated. > > Aidan MacNamara > EMBL-EBI >David Winsemius, MD Alameda, CA, USA