> before_mode=randomForest(逾期次数~大品牌+净车价+出生年月+性别+婚姻状况+最高学历+单位类型+个人税后月均收入+车贷+贷款期限+业务类型,data=trainbefore,importance=TRUE)
Error in y - ymean : non-numeric argument to binary operator
In addition: There were 13 warnings (use warnings() to see them)
新手求助，这个问题该如何解决？