recursion fibonacci python code example

Example 1: python recursive fibonacci function

# Python program to display the Fibonacci sequence

def recur_fibo(n):
   if n <= 1:
       return n
   else:
       return(recur_fibo(n-1) + recur_fibo(n-2))

nterms = 10

# check if the number of terms is valid
if nterms <= 0:
   print("Plese enter a positive integer")
else:
   print("Fibonacci sequence:")
   for i in range(nterms):
       print(recur_fibo(i))

Example 2: python fibonacci recursive

def Fibonacci( pos ):
        #check for the terminating condition
        if pos <= 1 :
                #Return the value for position 1, here it is 0
                return 0
        if pos == 2:
                #return the value for position 2, here it is 1
                return 1
 
        #perform some operation with the arguments
        #Calculate the (n-1)th number by calling the function itself
        n_1 = Fibonacci( pos-1 )
 
        #calculation  the (n-2)th number by calling the function itself again
        n_2 = Fibonacci( pos-2 )
 
        #calculate the fibo number
        n = n_1 + n_2
 
        #return the fibo number
        return n
 
#Here we asking the function to calculate 5th Fibonacci
nth_fibo = Fibonacci( 5 ) 
 
print (nth_fibo)

Example 3: fibonacci sequence python

# WARNING: this program assumes the
# fibonacci sequence starts at 1
def fib(num):
  """return the number at index num in the fibonacci sequence"""
  if num <= 2:
    return 1
  return fib(num - 1) + fib(num - 2)


print(fib(6))  # 8

Example 4: fibonacci recursive python

#fibonacci sequence with memory to increase the speed.
class recur_fibo:
    memory = {0: 1, 1:1}
    
    def fibonacci(n):
        if n in recur_fibo.memory:
            return recur_fibo.memory[n]
        else:
            recur_fibo.memory[n] = recur_fibo.fibonacci(n-1) + recur_fibo.fibonacci(n-2)
            return recur_fibo.memory[n]

if __name__ == "__main__":
    value = recur_fibo.fibonacci(200)
    print(value)