CODEWITHSUNDEEP
r
John Smith
John Smith

Reputation: 1

Writing a for loop for a numerical series in R

I'm not a R expert but I'm trying to understand the basics of the for-loop method. I'm trying to write a for-loop that prints the output as follows:

1 3 5 7 9 11

The code I am writing is below:

for (i in 1:3) {
  print(i)
  print(i + 2)
  }

However, I'm getting the below output based on my code:

1 3 2 4 3 5

It appears I am getting the first loop right but when it looks for i == 2 and i == 3 isn't not generating what I expect. What needs to be revised with my code so that my i == 2 and i == 3 is correct?

Upvotes: 0

Views: 225

Answers (3)

Uwe
Uwe

Reputation: 42544

The OP has asked to revise his code to generate the expected result.

He has written a for loop with 3 iterations to print 6 figures.

So, the first iteration has to print the numbers 1 and 3, the second iteration has to print the numbers 5 and 7, the third 9 and 11. Each iteration advances the output by 4.

OP's approach can be modified to return the expected result:

for (i in 1:3) {
  print(4 * (i-1) + 1)
  print(4 * (i-1) + 3)
}

or, less verbose 

for (i in 1:3) {
  print(4 * i - 3)
  print(4 * i - 1)
}

[1] 1
[1] 3
[1] 5
[1] 7
[1] 9
[1] 11

Upvotes: 1

AlexB
AlexB

Reputation: 3269

Using the logic implemented by Edward, you can achieve the same output with sapply:

sapply(1:6, function(i) print(i * 2 - 1))

Upvotes: 0

Edward
Edward

Reputation: 18663

I'm trying to write a for-loop that prints the output as follows:

1 3 5 7 9 11

This is one way:

for (i in 1:6) {
  print(i * 2 - 1)
}

[1] 1
[1] 3
[1] 5
[1] 7
[1] 9
[1] 11

If you want to print it all on one line, then you'll have to save the results first, then print.

x <- NULL
for (i in 1:6) {
  x[i] <- (i * 2 - 1)
}
print(x)

[1]  1  3  5  7  9 11

Upvotes: 2

Related Questions