Control Structures

Question 1

if

Answer 1

if (a > b) {
print(“a is greater than b”)
}

Question 2

if else

Answer 2

if (a > b) {
   print("a is greater than b")
} else {
print("b is greater than a")
}

Question 3

else if

Answer 3

if (a > b) {
   print("a is greater than b")
} else if (a < b) {
   print("b is greater than a")
} else if (a == b) {
   print("a and b are the same")
}

Question 4

loop: Print elements of a sequence

Answer 4

numbers

Question 5

Loop over rows of a data frame

Answer 5

for (i in 1:nrow(data_frame)) {
print(data_frame$variable_1[i] + data_frame$variable_2[i])
}

Question 6

Store for-loop output in a vector

Answer 6

output_vec

Question 7

for-loop with selection control structure

Answer 7

for (i in 1:nrow(data_frame) {
   if (a > b) {
      print("a is greater than b")
} else {
      print("b is greater than a")
      }
}

Question 8

for-loops with more than two cases

Answer 8

for (i in 1:nrow(data_frame)) {
   if (a > b) {
      print("a is greater than b")
   } else if (a < b) {
      print("b is greater than a")
   } else if (a == b) {
      print("a and b are the same")
   }
}

Question 9

Which are the 3 types of control structures?

Answer 9

Sequence operations
Selection operations
Repetition operations

Question 10

What do SEQUENCE operations do?

Answer 10

perform operation one after another in the order they are specified

Question 11

What do SELECTION operations do?

Answer 11

They test whether a specified condition is TRUE or FALSE and executes diferent action depending on that test outcome.

Question 12

What do REPETITION operations do?

Answer 12

Allows you to repeat blocks of codes depending on specified conditions.