Error in Eval(Expr, Envir, Enclos):Object Not Found

Error in eval(expr, envir, enclos) : object not found

Don't know why @Janos deleted his answer, but it's correct: your data frame Train doesn't have a column named pre. When you pass a formula and a data frame to a model-fitting function, the names in the formula have to refer to columns in the data frame. Your Train has columns called residual.sugar, total.sulfur, alcohol and quality. You need to change either your formula or your data frame so they're consistent with each other.

And just to clarify: Pre is an object containing a formula. That formula contains a reference to the variable pre. It's the latter that has to be consistent with the data frame.

dplyr Error in eval(expr, envir, enclos) : object '.' not found

Actually the error simply comes from your way of using the piping in the first command. The . (dot) refers to the previous result in the pipeline but there is nothing before your filter so it gives the error!

To get it work you can take the data.frame out of the filter function:

closing <- survey %>% filter(.[[47]] != 0, .[[48]] >= 10) %>% ...

I tested it with another dataset.

Error in eval(expr, envir, enclos) : object not found when using eval

Your issue is discussed, and solved, in the 'Programming with dplyr' vignette.

The bottomline is instead of quoting lag.ME.Jun yourself by referring to it using "lag.ME.Jun", you should rely on enquo(lag.ME.Jun) and !!lag.ME.Jun. However, this would mean that it should be in the function call.

Your function at several other points also refers to variables that are not created in the function environment (e.g. exchcd, date), so R will currently throw errors on any dataset that does not contain these variables. In general, it is unwise for functions to rely on inputs that were not part of the function call.

Error in eval(expr, envir, enclos) : object 'Tribe' not found

You want the colour of your points to vary by the variable state, so it should be inside the aes:

 geom_point(aes(colour = State))

Anything outside of the aes is constant, so, colour=red or size=2.

Error in eval(expr, envir, enclos) : object 'V2' not found

Your error comes from the rpart function.

From the rpart documentation:

Usage
rpart(formula, data, weights, subset, na.action = na.rpart, method,
  model = FALSE, x = FALSE, y = TRUE, parms, control, cost, ...) 
Arguments

formula:
a formula, with a response but no interaction terms. If this a a
data frome, that is taken as the model frame (see model.frame).

So you need something like:

data_train <- head(balance_data,100)
...
tree_model <- rpart(V1 ~ V2 + V3 + V4, data_train)

Depending on what are your model.