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rlogical-operatorsstringi

Select strings from list where logical value is TRUE

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.

Solution

  • 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"