Explanation:Use acast or dcast depending on whether you want vector/matrix/array output or data frame output. 9. Which of the following join is by default used in plyr package ?
A. left
B. right
C. full
D. All of the Mentioned
Answer:A
Explanation:Use acast or dcast depending on whether you want vector/matrix/array output or data frame output. 9. Which of the following join is by default used in plyr package ?
A. left B. right C. full D. All of the Mentioned
Explanation:Join is faster in plyr package. 10. mutate function is used for casting as multi dimensional arrays.