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Difficulty level:

Below are the solutions to these exercises on regular sequences.

#################### # # # Exercise 1 # # # #################### #Using the following variables: x=1 i=c(1:10) #For this exercise, write a for() loop that increments x in two for each i. for (j in i) x=x+2 x

## [1] 21

#################### # # # 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. for (j in i) {x=x+3 y=y-2} x

## [1] 31

```
y
```

## [1] 20

#################### # # # 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<b. for (a in 2:8) for (b in 1:6) if (a<b) cat(a,'less than',b,'\n')

## 2 less than 3 ## 2 less than 4 ## 2 less than 5 ## 2 less than 6 ## 3 less than 4 ## 3 less than 5 ## 3 less than 6 ## 4 less than 5 ## 4 less than 6 ## 5 less than 6

#################### # # # 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 = c (2,4,6), and the third x = (2,4,6,8). i=6 while (length(x)<12) { x=c(x,i) i=i+2 } x

## [1] 2 4 6 8 10 12 14 16 18 20 22 24

#################### # # # 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=c() i=1 j=6 while (i<7) { x[i]=a[i]*b[j] i=i+1 j=j-1 } x

## [1] 225 224 221 216 209 200

#################### # # # Exercise 6 # # # #################### #Using the following variable: a=1:10 #For this exercise, type a while () loop that computes a vector<code> 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] i=1 x=c() while (i<=10) { x[i]=sum(a[1:i]) i=i+1 } #################### # # # 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. repeat {x=x/i print(x) i=i-1 if (i==0) break }

## [1] 1 ## [1] 0.1111111 ## [1] 0.01388889 ## [1] 0.001984127 ## [1] 0.0003306878 ## [1] 6.613757e-05 ## [1] 1.653439e-05 ## [1] 5.511464e-06 ## [1] 2.755732e-06 ## [1] 2.755732e-06

#################### # # # 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<y. repeat { x=x-i y=y+i if (x<y) break } x

## [1] 74

```
y
```

## [1] 76

#################### # # # 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. y=as.Date("31/12/2017","%d/%m/%Y") repeat { x=x+1 if (x==y) break } #################### # # # 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]) y=c() for (i in 1:nrow(x)) y[i]=x[i,1]*sum(x[1:i,2]) y

## [1] 3 8 18 44 126 140 100 84

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swapna says

Regarding Exercise 8 solution, According to the problem statement i is incrementing but in the solution code we are not incrementing it.