Question

1. In R, you can choose almost any name you like for an object, as long as the name does not begin with a number or a special character like +, -, *, /, ^, !, @, or &.

Note: Remember that the most helpful names will remind you what you put in your object.

Which of these would be valid object names?

^-^

+1

foo

var

2. If your vector contains a sequence of contiguous integers, you can create it with the : shortcut. If run 1:5 in command line. What do you get?

1, 2, 3, 4, 5

[1] 1 2 3 4 5

1 : 5

3.

You can extract any element of a vector by placing pair of brackets behind the vector. Inside the brackets place the number of the element that you’d like to extract.

If you assign vec <- c(1, 2, 4, 8, 16), then vec[3] would return:

vec[3]

4

16

3

4.

Vector recycling: Predict what the code below will return.

1 + c(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)

1] 3 4 5 6 7 8 9 10 11 12

[1] 0 1 2 3 4 5 6 7 8 9

[1] 2 3 4 5 6 7 8 9 10 11

Answer 1

Vou h von [1 ] 1 2 3 4 5 (4 [1] 2 3 4 5 6 7 8 9 10 11

11LVIUUSTY yaved Workspace restored] > 1:5 [1] 1 2 3 4 5 > vec<-c(1,2,4,8,16) > vec[3] [1] 4 > 1+c(1,2,3,4,5,6,7,8,9,10) [1] 2 3 4 5 6 7 8 9 10 11