Swirl-R2

Question 1

square roor

Answer 1

sqrt()

Question 2

kada podelimo vec3 sa vec3

Answer 2

dobijemo vec3 u kom se prvi el prvog vektora deli sa prvim elementom drugog drugi sa drugim trci sa trecim

x

Question 3

function to get arguments of a function

Answer 3

args()

Question 4

dir.create(file.path(“folder1”,”folder2”),recursive=TRUE)

WHAT DOES IT DO

Answer 4

it creates two folders with folder 2 nested inside folder 1

Question 5

delete a directoery

Answer 5

unlink(“folder2”,recursive=TRUE)

Question 6

? for operators

Answer 6

?’:’

Question 7

we use sequence to set increment which cannot be done in :

Answer 7

seq(0,10,by=0.5)

Question 8

we can also set the length of the vector for example between 5 and 4 of length 10

Answer 8

seg(5,4,length=10)

Question 9

if we want to create a vector of 40 zeros

Answer 9

rep(0,times=40) or rep(9,40)

Question 10

rep(c(0,1,2),each=10) what does it do

Answer 10

00000000001111111111222222222

Question 11

vectors can be represented in atomic v and lists

Answer 11

atomic has only one data type while list has many

Question 12

if we have a char vec

Answer 12

paste(vec,collapse=” “)

Question 13

join two words

Answer 13

pastre(word1,word2,sep=” “)

Question 14

y

Answer 14

fin

Question 15

x[is.na(x)]

Answer 15

we get all NAs

y

Question 16

x[!is.na(x) & x>0]

Answer 16

all positive values that are not NAs

Question 17

base (vector) indexing in R

Answer 17

one-based-indexing

Question 18

x[c(-2, -10)]

Answer 18

all the elements of x except the 2nd and the 10th

or x[c(-2, -10)] exact same result

Question 19

stigla sam do matrices

Answer 19

ok