Error: At least one of the class levels is not a valid R variable name; This will cause errors when class probabilities are generated because the variables names will be converted..

The error message indicates that one or more of the levels in the class variable are not valid R variable names. When using R, variable names must start with a letter and contain only letters, numbers, and the dot (.) or underscore (_) characters.

To correct this R-code error, you’ll need to modify the levels of the class variable so that they are valid R variable names. One solution is to add this code:

# Replace invalid characters in class levels with underscores
levels(training$class) <- gsub("[^[:alnum:]]", "_", levels(training$class))

# Check that the levels are now valid R variable names
isValid <- sapply(levels(training$class), is.validName)
if (any(!isValid)) {
  stop("Class levels are still not valid R variable names")
}

Once you have corrected the levels, you should be able to run the rest of the code without encountering the “Error: At least one of the class levels is not a valid R variable name; This will cause errors when class probabilities are generated because the variables names will be converted..”