Scripting Loops exercises Vol.2

(This article was first published on R-exercises, and kindly contributed to R-bloggers)

450px-Invertigoloop

[For this exercise, first write down your answer, without using R. Then, check your answer using R.]

Answers to the exercises are available here.

Exercise 1

Using the following variables:

x=1
i=c(1:10)

For this exercise, write a for() loop that increments x by two for each i.

Exercise 2
Using the following variables:

x=1
y=40
i=c(1:10)

For this exercise, write a for() loop that increments x by three and decrease y by two, for each i.

Exercise 3
Using the following variables:

a,b

For this exercise, write a nested for() loop (where the outer for loop increment a from 2 to 8 by 1, and the
inner for loop increment b from 1 to 6 by 1) that print “a, ‘ less than ‘,b” if a

Exercise 4
Using the following variable:

x=c(2,4)

For this exercise, type a while () loop that adds even numbers to x, while the length of x is less than 12.
For example, in the first iteration you get x = 2,4,6, and the third x =2,4,6,8.

Exercise 5

Using the following variable:

a=15:10
b=20:15

For this exercise, type a while () loop that computes a vector x=225 224 221 216 209 200 ,such that


x[1]=a[1]*b[6]
x[2]=a[2]*b[5]
x[3]=a[3]*b[5]
.
.
x[6]=a[6]*b[1]

Exercise 6

Using the following variable:

a=1:10

For this exercise, type a while () loop that computes a vector x=1 3 6 10 15 21 28 36 45 55 ,such that

x[1]=a[1]
x[2]=a[1]+a[2]
x[3]=a[1]+a[2]+a[3]
.
.

Exercise 7

Using the following variable:

i=10
x=10

For this exercise, type a repeat () loop that decreasing i computes x=x/i until i=0.

Exercise 8

Using the following variable:

x=100
y=50
i=1

For this exercise, type a repeat () loop that incrementing i computes x=x-i and y=y+i until x.

Exercise 9

Using the following variable:

x=as.Date("10/11/2017","%d/%m/%Y")

For this exercise, type a repeat () loop that increment x until x is equal to 31/12/2017.

Exercise 10

Using the following variable:


x=cbind(c(1,2,3,4,9,7,4,3),c(3,1,2,5,3,6,5,3))

For this exercise, type a for() loop that calculate y=3 8 18 44 126 140 100 84, such that

y[1]=x[1,1]*x[1,2]
y[2]=x[2,1]*sum(x[1:2,2])
y[3]=x[3,1]*sum(x[1:3,2])
.
.
.
y[8]=x[8,1]*sum(x[1:8,2])

Want to practice loops a bit more? We have more exercise sets on this topic here.

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