Train a random forest algorithm using various columns - r

Question

I have asked this question before here: Creating a loop for different random forest training algoritms but didnt get a right answer yet. So hereby another attempt with a more reproducable example.
I have the following datasets:
train <- read.csv(url("http://s3.amazonaws.com/assets.datacamp.com/course/Kaggle/train.csv"))
test <- read.csv(url("http://s3.amazonaws.com/assets.datacamp.com/course/Kaggle/test.csv"))
train <- train[complete.cases(train), ]
I would like to run several random forest algoritms to see which one performs best. So what I basically want to do is:
#predict based on Pclass
fit <- randomForest(as.factor(Survived) ~ Pclass, data=train, importance=TRUE, ntree=2000)
Prediction <- predict(fit, test)
#fetch accuracy
#predict based on Pclass and Sex
fit <- randomForest(as.factor(Survived) ~ Pclass + Sex, data=train, importance=TRUE, ntree=2000)
Prediction <- predict(fit, test)
#fetch accuracy
I would like to create some kind of loop so that I can store all values in a list and then loop over it. So like this:
list <- c(Pclass, Pclass + Sex)
for (R in list) {
modfit <- paste0("won ~ ", R, ", data=training, method=\"rf\", prox=\"TRUE")
modfit <- as.formula(modfit)
train(modfit)
}
But the code above doesn't work. It gives me the following error:
Error in parse(text = x, keep.source = FALSE) :
<text>:1:13: unexpected ','
1: won ~ Pclass,
Any thoughts on how I can get this working?

Answer 1

for (R in list) {
modfit <- paste0("won ~ ", R, "data=training, method=\"rf\", prox=\"TRUE")
modfit <- as.formula(modfit)
train(modfit)
}
You might be having a comma before data=training that does not need to be there