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rsapplystrsplit

"subscript out of bounds" on character vector

I have a vector "nameAlpha" such as c("Mark Twain", "Phil Hall", "Michael P. O'Connor", " ",...). I want to pass each first name to another vector "nameAlpha_first". I run this

nameAlpha_first <- sapply(strsplit(nameAlpha, "\\s+"), "[[", 1)

But I get 

Error in FUN(X[[12L]], ...) : subscript out of bounds

Could it be because few elements of the vector are empty? How I move to fix it?

Solution

  • Assume we define and preprocess a character vector as such:

    nameAlpha<-c("Mark Twain", NA, "Phil Hall", 
             "Michael P. O'Connor", " ", "", NA, "John")
nameAlpha[which(nchar(nameAlpha)<2)]<-NA

    You should write 

    sapply(strsplit(nameAlpha, "\\s+"), head, n=1)

    And it will work. If you want the last name you can do

    sapply(strsplit(nameAlpha, "\\s+"), tail, n=1)

    which will provide you with the vector of last names.