R将列表转换为连续元素对

Question

With the list

lst <- list("a","b","c","a","b","b")

I'm looking for a transformation listing all possible pairs of successors from the list

a b    ( 1st and 2nd elements)
b c    ( 2nd and 3rd elements)
c a    ( 3rd and 4th elements)
a b    ( 4th and 5th elements)
b b    ( 5th and 6th elements)

so when the list contains N elements, I'm expecting N-1 pairs - Thx

Answer 1

You can do...

Map(c, head(lst, -1), tail(lst, -1))

[[1]]
[1] "a" "b"

[[2]]
[1] "b" "c"

[[3]]
[1] "c" "a"

[[4]]
[1] "a" "b"

[[5]]
[1] "b" "b"

Alternately, ...

embed(lst, 2)

     [,1] [,2]
[1,] "b"  "a" 
[2,] "c"  "b" 
[3,] "a"  "c" 
[4,] "b"  "a" 
[5,] "b"  "b"