Remove duplicated elements from list

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I have a list of character vectors:

my.list <- list(e1 = c("a","b","c","k"),e2 = c("b","d","e"),e3 = c("t","d","g","a","f"))

And I'm looking for a function that for any character that appears more than once across the list's vectors (in each vector a character can only appear once), will only keep the first appearance.

The result list for this example would therefore be:

res.list <- list(e1 = c("a","b","c","k"),e2 = c("d","e"),e3 = c("t","g","f"))

Note that it is possible that an entire vector in the list is eliminated so that the number of elements in the resulting list doesn't necessarily have to be equal to the input list.

redundancy r list
3 Answers

I found the solutions here very complex for my understanding and sought a simpler technique. Suppose you have the following list.

my_list <- list(a = c(1,2,3,4,5,5), b = c(1,2,2,3,3,4,4), 
                
                d = c("Mary", "Mary", "John", "John"))

The following much simpler piece of code removes the duplicates.

sapply(my_list, unique)

You will end up with the following.

$a
[1] 1 2 3 4 5

$b
[1] 1 2 3 4

$d
[1] "Mary" "John"

There is beauty in simplicity!

user_132169310
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