For循环以子集数据帧列表

Question

我有一个数据框列表：

df1<-data.frame("A"=1:10, "B"=c("Mark","John","Lucas","Helen","Rachel","Leyla","Tina","Fanny","Emma","Kate"),"C"=c(91:100))
df2<-data.frame("A"=1:8, "B"=c("Mark","John","Lucas","Helen","Rachel","Leyla","Tina","Fanny"),"C"=c(93:100))
df3<-data.frame("A"=1:3, "B"=c("Mark","John","Lucas"),"C"=c(98:100))
all_df<-list(df1,df2,df3)

我想创建一个按列子集的数据框的新列表，如下所示：

df1_sub<-df1[,c("B","C")]
df2_sub<-df1[,c("B","C")]
df3_sub<-df1[,c("B","C")]
all_df_sub<-list(df1_sub,df2_sub,df3_sub)

最后为每个新的 dataframe 分配其名称：

mynames<-c("df1_sub","df2_sub","df3_sub")
names(all_df_sub)<-mynames

我想使用lapply和for循环来做到这一点，但我无法弄清楚如何，因为我在定义 function 和子集数据帧列表之间的某个地方陷入困境（我对此不是很有信心，我检查了较旧的类似没有成功的问题）。 到目前为止，这是我正在尝试的：

all_df_sub<-lapply(all_df, function(all_df){
  for([[i]] in all_df) {
    a<-[[i]][,c("B","C")]
    } 
  all_df } )

任何建议将不胜感激。 谢谢！

Answer 1

你可以试试这个：

all_df_sub <-lapply(all_df, function(dat){dat[2:3]})
all_df_sub <-setNames(all_df_sub, c("df1_sub","df2_sub","df3_sub"))