Select strings from list where logical value is TRUE

Question

I would like to extract duplicated strings from a list. As, the unique function does not work on non-numerical data, I used the stringi package with the stri_duplicated function to obtain logical values (TRUE or FALSE). I would like to extract the strings that are duplicated from the list (the strings for which stri_duplicated reports a TRUE).

Here a minimal example:

ex1 <- c("SE1", "SE2", "SE5", "SE2")
dupl <- stri_duplicated(ex1)

> dupl
[1] FALSE FALSE FALSE  TRUE

Many thanks in advance.

What do you mean `unique` does not work for non-numeric. Did you try `unique(ex1)`? — Sotos, Jul 14 '20 at 14:00
I was wrong. I tried it once more and now it worked just fine. — ABiologist, Jul 14 '20 at 14:12

score -1 · Accepted Answer · answered Jul 14 '20 at 14:00

-1

In base-R there is

duplicated(ex1)
[1] FALSE FALSE FALSE  TRUE

if you want to extract the duplicated items

ex1[duplicated(ex1)]
[1] "SE2"

answered Jul 14 '20 at 14:00

Daniel O

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If the downvoter cares to comment why they think this is a poor answer, I would be happy to address it. – Daniel O Jul 14 '20 at 14:09

Select strings from list where logical value is TRUE

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