ETbyg <- ET %>%
  group_by(上市公司代码_Comcd) %>%
  mutate(Plag1=lag(Pt1,1))
然后ET里面我在前面命名了Pt1.
colnames(ET)<-c("上市公司代码_Comcd","证监会行业门类代码_Csrciccd1","日期_Date","RET",
               "收盘价_Clpr", "Pt1","复权价2.元._AdjClpr2","年份_year","E","年份_year")
请问应该怎么修改