For 循环以对数据帧列表进行子集化

Question

我有一个数据帧列表：

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)

我想创建一个新的数据框列表，按列划分子集，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)

最后为每个新数据框分配名称：

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，但我不知道如何做，因为我被困在定义函数和子集数据帧列表之间的某个地方（我对此不是很有信心，我检查了较早的类似问题但没有成功）。这是我目前正在尝试的：

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

如有任何建议，我们将不胜感激。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"))

For 循环以对数据帧列表进行子集化

For loop to subset a list of dataframes

r

list

subset

dataframe