removing outlier function / dataset update

Hi,

I have a few lines of code that will remove outliers for a regression test
based on the studentized residuals being above or below 3, -3. I have to do
this multiple times and have attempted to create a function to lessen the
amount of copying, pasting and replacing.

I run into trouble with the function and receiving the error "Error in
`$<-.data.frame`(`*tmp*`, "varpredicted", value = c(0.114285714285714, ?:
?replacement has 20 rows, data has 19
"

any help would be appreciated. a list of code is listed below.

Thank you for your time!

x = c(1:20)
y = c(1,3,4,2,5,6,18,8,10,8,11,13,14,14,15,85,17,19,19,20)
data1 = data.frame(x,y)

# remove outliers for regression by studentized residuals being greater than
3
data1$predicted = predict(lm(data1$y~data1$x))
data1$stdres = rstudent(lm(data1$y~data1$x));
i=length(which(data1$stdres>3|data1$stdres< -3))
while(i >= 1){
? ? ? ?remove<-which(data1$stdres>3|data1$stdres< -3)
? ? ? ?print(data1[remove,])
? ? ? ?data1 = data1[-remove,]
? ? ? ?data1$predicted = predict(lm(data1$y~data1$x))
? ? ? ?data1$stdres = rstudent(lm(data1$y~data1$x))
? ? ? ?i = with(data1,length(which(stdres>3|stdres< -3)))
?}

# attemp to create a function to perfom same idea as above
rm.outliers = function(dataset,var1, var2) {

?dataset$varpredicted = predict(lm(var1~var2))
?dataset$varstdres = rstudent(lm(var1~var2))
?i = length(which(dataset$varstdres > 3 | dataset$varstdres < -3))
?while(i >= 1){
? ? ? ? removed = which(dataset$varstdres > 3 | dataset$varstdres < -3)
? ? ? ? print(dataset[removed,])
? ? ? ? dataset = dataset[-removed,]
? ? ? ? dataset$varpredicted = predict(lm(var1~var2))
? dataset$varstdres = rstudent(lm(var1~var2))
? ? ? ? i = with(dataset,length(varstdres > 3 | varstdres < -3))
? }
}
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