Konvertieren von Zeilen in eine kategoriale Spalte mit R

Ich habe ein transkribiertes Interview und die Daten sind wie folgt organisiert:

[1,] "Interviewer"
[2,] "What is your favorite food?"
[3,] "Interviewee"
[4,] "I love to eat pizza"
[5,] "Interviewer"
[6,] "Cool. But have you ever tried eating salad?"
[7,] "Interviewee "
[8,] "Yeah..."
[9,] "Interviewer"
[10,] "I love salad, pizza is bad."
[11,] "Interviewee "
[12,] "I don't totally agree" 

Ich möchte den Autor der Rede aus den Zeilen entfernen und ihn in eine kategoriale Spalte umwandeln, wie im Beispiel:

 [,1] [,2] 
[1,] "Interviewer" "What is your favorite food?"
[2,] "Interviewee" "I love to eat pizza"
[3,] "Interviewer" "Cool. But have you ever tried eating a salad?"
[4,] "Interviewee" "Yeah..."
[5,] "Interviewer" "I love salad, pizza is bad."
[6,] "Interviewee" "I don't totally agree"

Das Interview betrachtet das Gespräch zwischen zwei Personen. Weiß jemand, wie das geht? Danke im Voraus!

Lösung des Problems

Hier ist ein alternativer Ansatz:

library(tidyverse)
tibble(v1 = v1) %>% 
 mutate(v2 = lead(v1)) %>% 
 filter(row_number() %% 2 == 1) %>% 
 as.matrix()

 v1 v2   
[1,] "Interviewer" "What is your favorite food?" 
[2,] "Interviewee" "I love to eat pizza"  
[3,] "Interviewer" "Cool. But have you ever tried eating salad?"
[4,] "Interviewee " "Yeah..."   
[5,] "Interviewer" "I love salad, pizza is bad." 
[6,] "Interviewee " "I don't totally agree"