CODEWITHSUNDEEP
r
Barnaby
Barnaby

Reputation: 1480

Append individual vectors in a list to specific positions within another list

I would like to append to z the below list, however one sublist at a time in specific locations within z. I tried to do this with the below expression however I can not manage to have this in proper order. 

z <- list (c(3,2,1), c(4,6,5), c(7,8,9), c(3,2,1), c(4,6,5), c(7,8,9))
y <- list (c("A","B","C"), c("D","E","F"), c("h","i","j"))

fun <- function (x) append (z , y[[x]] , c(0,2,4))
lapply (seq(length( y )) , fun )

# Desired Output
x
[[1]]
[1] "A","B","C

[[2]]
[1] 3 2 1

[[3]]
[1] 4 6 5

[[4]]
[1] "D","E","F"

[[5]]
[1] 7 8 9

[[6]]
[1] 3 2 1

[[7]]
[1] "h","i","j"

[[8]]
[1] 4 6 5

[[9]]
[1] 7 8 9

Upvotes: 3

Views: 54

Answers (2)

Veerendra Gadekar
Veerendra Gadekar

Reputation: 4472

Here is another option

c(y,z)[order(c(seq_along(y),rep(1:length(y), each = 2)))]

#[[1]]
#[1] "A" "B" "C"
#
#[[2]]
#[1] 3 2 1
#
#[[3]]
#[1] 4 6 5
#
#[[4]]
#[1] "D" "E" "F"
#
#[[5]]
#[1] 7 8 9
#
#[[6]]
#[1] 3 2 1
#
#[[7]]
#[1] "h" "i" "j"
#
#[[8]]
#[1] 4 6 5
#
#[[9]]
#[1] 7 8 9

Upvotes: 3

akrun
akrun

Reputation: 887213

We can try

v1 <- c(0,2,4)
v2 <- v1 + seq_along(v1)-1
for(i in seq_along(y)) z <- append(z,y[i], v2[i])
z
#[[1]]
#[1] "A" "B" "C"

#[[2]]
#[1] 3 2 1

#[[3]]
#[1] 4 6 5

#[[4]]
#[1] "D" "E" "F"

#[[5]]
#[1] 7 8 9

#[[6]]
#[1] 3 2 1

#[[7]]
#[1] "h" "i" "j"

#[[8]]
#[1] 4 6 5

#[[9]]
#[1] 7 8 9

Upvotes: 2

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