Unable to cast object of type ‘System.String’ to type ‘System.Boolean’

Error in if (series_types_datafarme$type[series_types_datafarme$var == : argument is of length zero

Error in readRDS(model URl port) : ‘file’◆◆◆◆◆◆◆

Error in eval(family$initialize) : y值必需满足0 <= y <= 1

Error in gbm.unify(model, data):Models built on data with categorical features are not supported – please encode them before training.

导入数据：’utf-8′ codec can’t decode byte 0xa1 in position 10971: invalid start byte

在回归分析中，如何修改分类变量的参照/参考/ref因子