R：如何对列表中的所有数据帧进行子集化？

Question

我有一个名为WaFramesCosts的数据框列表。我想简单地将其子集化以显示特定的列，以便我可以导出它们。我试过了：

    for (i in names(WaFramesCosts)) {
      WaFramesCosts[[i]][,c("Cost_Center","Domestic_Anytime_Min_Used","Department",
"Domestic_Anytime_Min_Used")]

    }

但它返回错误

Error in `[.data.frame`(WaFramesCosts[[i]], , c("Cost_Center", "Department",  : 
  undefined columns selected

我也尝试过：

for (i in seq_along(WaFramesCosts)){
WaFramesCosts[[i]][ , -which(names(WaFramesCosts[[i]]) %in% c("Cost_Center","Domestic_Anytime_Min_Used","Department",
    "Domestic_Anytime_Min_Used"))]

但是我得到了同样的错误。谁能看到我做错了什么？

旁注：作为参考，我使用了这个：

for (i in seq_along(WaFramesCosts)) {
    t <- WaFramesCosts[[i]][ , grepl( "Domestic" , names( WaFramesCosts[[i]] ) )] 
    q <- subset(WaFramesCosts[[i]], select = c("Cost_Center","Domestic_Anytime_Min_Used","Department","Domestic_Anytime_Min_Used"))  

    WaFramesCosts[[i]] <- merge(q,t)
  }

用不同的方法尝试相同的目标，似乎越来越接近。