How to get the nth element of each item of a list, which is itself a vector of unknown length

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-上瘾入骨i
-上瘾入骨i 2021-01-02 06:08

If we have a list, and each item can have different length. For example:

l <- list(c(1, 2), c(3, 4,5), c(5), c(6,7))

(In order to be cl

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  •  北海茫月
    2021-01-02 07:08

    We can create a function using sapply

    fun1 <- function(lst, n){
             sapply(lst, `[`, n)
       }
    fun1(l, 1)
    #[1] 1 3 5 6
    
    fun1(l, 2)
    #[1]  2  4 NA  7
    

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