代码
table0<-epicalc::tableStack(vars=sapply(c("Exam_fage_gp","Exam_fedu_level","Exam_fjob","Exam_fbmi","Exam_year","Exam_fmarry_age_gp","Exam_pregnancy_age_gp"," Exam_fage_difference_age_gp"),function(x) which(x==names(data))),by=IO,decimal=2,na.rm=FALSE)
出现错误：Error in .subset(x, j) : invalid subscript type 'list'。