# How to combine list elements of different sizes in R?

To combine list elements of different sizes in R, we can use expand.grid function. For Example, if we have a list called LIST that contains elements of different sizes then we can combine those items by using the command given below −

expand.grid(LIST)

## Example 1

To combine list elements of different sizes in R, use the following snippet −

List1<-list(x1=rpois(2,2),x2=rpois(2,10),x3=rpois(1,2),x4=rpois(3,5),x5=rpois(2,5))
List1

The respective Outputs as per the sizes will be as follows −

$x1  2 3$x2
 6 7
$x3  2$x4
 2 4 4
$x5  3 5 Now, to combine elements of List1 add the following code to the above snippet − List1<-list(x1=rpois(2,2),x2=rpois(2,10),x3=rpois(1,2),x4=rpois(3,5),x5=rpois(2,5)) expand.grid(List1) ## Output If you execute all the above given snippets as a single program, it generates the following Output −  x1 x2 x3 x4 x5 1 2 6 2 2 3 2 3 6 2 2 3 3 2 7 2 2 3 4 3 7 2 2 3 5 2 6 2 4 3 6 3 6 2 4 3 7 2 7 2 4 3 8 3 7 2 4 3 9 2 6 2 4 3 10 3 6 2 4 3 11 2 7 2 4 3 12 3 7 2 4 3 13 2 6 2 2 5 14 3 6 2 2 5 15 2 7 2 2 5 16 3 7 2 2 5 17 2 6 2 4 5 18 3 6 2 4 5 19 2 7 2 4 5 20 3 7 2 4 5 21 2 6 2 4 5 22 3 6 2 4 5 23 2 7 2 4 5 24 3 7 2 4 5 ## Example 2 To combine list elements of different sizes in R, use the following snippet − List2<-list(y1=0:2,y2=c(1,2),y3=c(2,3,4,5)) List2 The respective ## Output s as per the sizes will be as follows − $y1
 0 1 2
$y2  1 2$y3
 2 3 4 5

To combine elements of List2 add the following code to the above snippet −

List2<-list(y1=0:2,y2=c(1,2),y3=c(2,3,4,5))
expand.grid(List2)

## Output

If you execute all the above given snippets as a single program, it generates the following Output −

  y1 y2 y3
1 0 1 2
2 1 1 2
3 2 1 2
4 0 2 2
5 1 2 2
6 2 2 2
7 0 1 3
8 1 1 3
9 2 1 3
10 0 2 3
11 1 2 3
12 2 2 3
13 0 1 4
14 1 1 4
15 2 1 4
16 0 2 4
17 1 2 4
18 2 2 4
19 0 1 5
20 1 1 5
21 2 1 5
22 0 2 5
23 1 2 5
24 2 2 5