CODEWITHSUNDEEP
rloopslapply
GabyLP
GabyLP

Reputation: 3781

r- lapply over a list

I have a table like:

ex

                                          dir      E_numdir
45 OCAMPO 1253 2                                    1253, 2
74 BENITO LYNCH 1883                                   1883
24 PRESIDENTE DE LA PLA 148                             148

Where E_numdir is a character I need to evaluate last 2 digits from each number in E_numdir, if they are 0 then get a mark in another column.

To evaluate this I tried:

lapply(ex$E_numdir , function(w) str_sub(w, -2, -1))

But I get the last 2 digits only from the last number.

So I tried:

lapply(as.vector(unlist(strsplit(ex$E_numdir,",")),mode="list") , function(w) str_sub(w, -2, -1))

But I get more rows than those I had. One for each element.

I need to get another column 'xx' with

                                          dir      E_numdir   xx
45 OCAMPO 1253 2                                    1253, 2   53,2
74 BENITO LYNCH 1883                                   1883   83 
24 PRESIDENTE DE LA PLA 148                             148   48

How can I apply the function to all the numbers but store the result in the same row?

thanks.

Upvotes: 0

Views: 92

Answers (1)

Rich Scriven
Rich Scriven

Reputation: 99321

You could do

library(stringi)

ex$last2 <- vapply(
    ## split on ", " - comma then a space
    stri_split_fixed(ex$E_numdir, ", "),
    ## paste the last two characters of each element together
    function(x) stri_c(stri_sub(x, -2), collapse = ","),
    ## set the return value for vapply()
    character(1L)
)

which gives

                          dir E_numdir last2
1            45 OCAMPO 1253 2  1253, 2  53,2
2        74 BENITO LYNCH 1883     1883    83
3 24 PRESIDENTE DE LA PLA 148      148    48

Upvotes: 2

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