CODEWITHSUNDEEP
r
Stataq
Stataq

Reputation: 2307

how to get none empty list from a list of list

I have a list which contain a list of list. The structure looks like this: enter image description here

Is it possible to create a with none empty list of list in it?

I tried datalist2 <- datalist[!is.na(datalist[[]])] which return 0 list, and datalist2 <- datalist[!is.na(datalist[[]])] whih return 5 lists(no changes). How can I only get 3 lists?

Any suggestion?

Upvotes: 0

Views: 27

Answers (2)

Benjamin Christoffersen
Benjamin Christoffersen

Reputation: 4841

You can use sapply and length and then select those with non-zero length:

# create an example
dat <- list(list(1:3), list(), list(letters[1:4]), list(LETTERS[1:4]), 
            list(), list())
str(dat)
#R> List of 6
#R>  $ :List of 1
#R>   ..$ : int [1:3] 1 2 3
#R>  $ : list()
#R>  $ :List of 1
#R>   ..$ : chr [1:4] "a" "b" "c" "d"
#R>  $ :List of 1
#R>   ..$ : chr [1:4] "A" "B" "C" "D"
#R>  $ : list()
#R>  $ : list()

# get the non-empty lists
res <- dat[sapply(dat, length) > 0]

# show the results
str(res)
#R> List of 3
#R>  $ :List of 1
#R>   ..$ : int [1:3] 1 2 3
#R>  $ :List of 1
#R>   ..$ : chr [1:4] "a" "b" "c" "d"
#R>  $ :List of 1
#R>   ..$ : chr [1:4] "A" "B" "C" "D"

Upvotes: 1

MonJeanJean
MonJeanJean

Reputation: 2906

You might wanna use purrr:

datalist2 <- datalist[!purrr:is_empty(datalist[[]])]

Don't know if it works though, could you please provide a sample?

Upvotes: 0

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