fibonacci function in python code example

Example 1: 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)

# method 2: use `for` loop
def fib2(num):
	a, b = 1, 1
	for _ in range(num - 1):
		a, b = b, a + b
	return a


print(fib(6))  # 8
print(fib2(6))  # same result, but much faster

Example 2: python fibonacci

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