R如何创建包含列表列的数据框？

Question

This is my current work around:

> df=data.frame(a=1)
> df$b = list(list(2,'a'))
> df
  a    b
1 1 2, a

It works, and I don't really mind that df=data.frame(a=1,b=list(list(1,'a'))) doesn't work .

But referencing b requires [[]] notation, like this: df$b[[1]] .

I'm looking for a solution that would allow simply df$b .

Answer 1

What you're looking for is not possible. If you use lists, you will need to use the [[]] notation. Otherwise, you can transform the elements of df$b using the command unlist() .

> df$b
[[1]]
[[1]][[1]]
[1] 2

[[1]][[2]]
[1] "a" 

> unlist(df$b)
[1] "2" "a"
> unlist(df$b)[1]
[1] "2"
> unlist(df$b)[2]
[1] "a"