[R] Extract every 2 element for a list which are not equal in length

[Mohammad Tanvir Ahamed]

Hi,

a <- c(1:5)b <- c(1:3)
c <- 1
d <- 5
e <- list(a,b,c,d)

# To extract every 1st element 
lapply(e,"[[",1)

## Out-put 
[[1]] 
[1] 1 

[[2]] 
[1] 1 

[[3]] 
[1] 1 

[[4]] 
[1] 5
 
#To extract every 2nd element (Need help in this case)
lapply(e,"[[",2)

## Expected outcome 
[[1]] 
[1] 2 

[[2]] 
[1] 2 

[[3]] 
[1] NA 

[[4]] 
[1] NA 



Any help will be appreciated . Thanks 


Tanvir Ahamed 
Göteborg, Sweden  |  mashranga at yahoo.com