Error in names(preds) <- allvars[-1] : 'names' attribute  must be the same length as the vector 
No missing data, all features are integers. 'names' attibute , here 8 means the number of features, if I get rid of one feature, the Error would be: 'names' attribute  must be the same length as the vector . I don't understand where the vector comes? would you please be so kind to help me to solve this question?