seq(0, 100, 10)
[1] 0 10 20 30 40 50 60 70 80 90 100
Jeffrey R. Stevens
February 6, 2023
Make a sequence from 0 to 100 in steps of 10.
Create a repetition of “yes” and “no” with 10 instance of each, alternating between the two. Then make one with 10 “yes” and then 10 “no”.
[1] "yes" "no" "yes" "no" "yes" "no" "yes" "no" "yes" "no" "yes" "no"
[13] "yes" "no" "yes" "no" "yes" "no" "yes" "no"
[1] "yes" "yes" "yes" "yes" "yes" "yes" "yes" "yes" "yes" "yes" "no" "no"
[13] "no" "no" "no" "no" "no" "no" "no" "no"
Add the argument n = 10
to head(mtcars)
. What does this do?
mpg cyl disp hp drat wt qsec vs am gear carb
Mazda RX4 21.0 6 160.0 110 3.90 2.620 16.46 0 1 4 4
Mazda RX4 Wag 21.0 6 160.0 110 3.90 2.875 17.02 0 1 4 4
Datsun 710 22.8 4 108.0 93 3.85 2.320 18.61 1 1 4 1
Hornet 4 Drive 21.4 6 258.0 110 3.08 3.215 19.44 1 0 3 1
Hornet Sportabout 18.7 8 360.0 175 3.15 3.440 17.02 0 0 3 2
Valiant 18.1 6 225.0 105 2.76 3.460 20.22 1 0 3 1
Duster 360 14.3 8 360.0 245 3.21 3.570 15.84 0 0 3 4
Merc 240D 24.4 4 146.7 62 3.69 3.190 20.00 1 0 4 2
Merc 230 22.8 4 140.8 95 3.92 3.150 22.90 1 0 4 2
Merc 280 19.2 6 167.6 123 3.92 3.440 18.30 1 0 4 4
Create a vector called dog_names
with the values Bella, Daisy, and Max.
Create a vector called sex
with the values Female, Male, and Male.
Use the index operator to print to console only Daisy and Max from dog_names
.
Replace the Daisy entry with Luna and print dog_names
to console.
Copy/paste and run this code: (mylist <- list(a = 1:4, b = c(4, 3, 8, 5), c = LETTERS[10:15], d = c("yes", "yes")))
$a
[1] 1 2 3 4
$b
[1] 4 3 8 5
$c
[1] "J" "K" "L" "M" "N" "O"
$d
[1] "yes" "yes"
Check the data types for each list element individually.
[1] "integer"
[1] "double"
[1] "character"
[1] "character"
Check the data types for each list element with one command.
List of 4
$ a: int [1:4] 1 2 3 4
$ b: num [1:4] 4 3 8 5
$ c: chr [1:6] "J" "K" "L" "M" ...
$ d: chr [1:2] "yes" "yes"
Combine list elements a
and b
into a single vector.
Create a data frame called mydf
with three columns: x
, y
, and z
and five rows. For x
assign any five numbers, for y
assign any five character strings, and for z
assign any five logical values.
(mydf <- data.frame(x = sample(1:10, 5, replace = TRUE), y = sample(letters, 5), z = sample(c(TRUE, FALSE), 5, replace = TRUE)))
x y z
1 5 l TRUE
2 3 c TRUE
3 4 m FALSE
4 4 w TRUE
5 5 j FALSE
Create a data frame called dogs
that combines the dog_names
and sex
vectors and print to console.
Print to console just Luna’s row.
Print to console the number of rows in dogs
.