Vectors

Question 1

What is a vector?

Answer 1

One dimensional array

Question 2

Can a single vector hold elements of multiple data types?

Answer 2

No

Question 3

What is the function to create a vector?

Answer 3

c()

Ex: c(“a”, “b”, “c”)

Question 4

What is the function to name elements of a vector?

Answer 4

names()

Ex: names(my_vector) <- c(“name1”, “name2”)

Question 5

What happens when two vectors are added, subtracted, etc.?

Ex: c(1, 2, 3) + c(4, 5, 6)

Answer 5

The result is calculated element-wise.

Ex Result: 5, 7, 9 is printed

Question 6

Which function sums all elements in a vector?

Answer 6

sum()

Ex: sum(my_vector)

Question 7

What index do vectors in R start at?

Answer 7

1

Question 8

How can you select a single element from a vector?

Answer 8

[num]

Ex: my_vector[2] OR my_vector[“Monday”]

Question 9

How can you select multiple out-of-sequence elements from a vector?

Answer 9

[c()]

Ex: my_vector[c(1, 5)] OR my_vector[c(“Monday”, “Wednesday”)] OR my_vector[c(TRUE, FALSE, TRUE)]

Question 10

How can you select multiple in-sequence elements from a vector?

Answer 10

[num1:num2]

Ex: my_vector[2:5]

Question 11

What happens when a vector is compared to a single object?

Ex: c(1, 3, 5) > 4

Answer 11

Each element in the vector is compared to the object.

Ex Result: FALSE FALSE TRUE is printed