CODEWITHSUNDEEP
rfibonacci
user17416440
user17416440

Reputation:

R function to find Fibonacci numbers

New to R, so apologies for any mistakes. I am making a R function to find 20 Fibonacci numbers starting from 1. I made this function, however the function outputs Fibonacci numbers like this:

# Output
1  1  2  3  5  8  13   21   34   55   89  144  233  377  610  987 1597 2584 4181 6765

I want this:

1  2  3  5  8  13   21   34   55   89  144  233  377  610  987 1597 2584 4181 6765 10946

What troubles me is I don't want 2 'ones' at start. Only one "1" at start is required. Also, having trouble in function calling. Here is my code:

Ms <- function(moving_sum) {
  Fib <- numeric(20)
  Fib[1]  <- Fib[2] <- 1
  for (i in 3:20) Fib[i] <- Fib[i - 2] + Fib[i - 1] 
  return(Fib)
}

Ms(0)

Thanks.

--- Update ---

How to find the total count of even numbers? And the total sum of those even numbers?

Upvotes: 0

Views: 956

Answers (3)

Irina Max
Irina Max

Reputation: 111

# You need to define first few cases only, and then it's simple
fibonacci <- function(n) {
      if (n <= 0) return(numeric(0))
      if (n == 1) return(0)
      if (n == 2) return(c(0, 1))
      
      fib <- numeric(n)
      fib[1] <- 0
      fib[2] <- 1
      
      for (i in 3:n) {
        fib[i] <- fib[i-1] + fib[i-2]
      }
      
      return(fib)
    }

Upvotes: 0

ThomasIsCoding
ThomasIsCoding

Reputation: 101753

Try the code below

Ms <- function() {
  Fib <- numeric(20)
  Fib[1:2] <- 1:2
  for (i in 3:20) Fib[i] <- Fib[i - 2] + Fib[i - 1]
  evenFibs <- Fib[Fib %% 2 == 0]
  list(
    Fibs = Fib,
    nrOfFibs = length(evenFibs),
    sumEvenFibs = sum(evenFibs)
  )
}

and you will get

> Ms()
$Fibs
 [1]     1     2     3     5     8    13    21    34    55    89   144   233
[13]   377   610   987  1597  2584  4181  6765 10946

$nrOfFibs
[1] 7

$sumEvenFibs
[1] 14328

Upvotes: 0

Onyambu
Onyambu

Reputation: 79238

incorporate the following changes

Ms <- function(moving_sum) {
  Fib <- numeric(moving_sum + 1) # Use the parameter moving_sum
  Fib[1]  <- Fib[2] <- 1
  for (i in seq(3, moving_sum + 1)) Fib[i] <- Fib[i - 2] + Fib[i - 1] 
  return(Fib[-1]) # Remove the first number
}

Ms(20)
 [1]     1     2     3     5     8    13    21    34    55    89   144   233   377
[14]   610   987  1597  2584  4181  6765 10946

Upvotes: 1

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