Reputation: 101
I'm tackling this following question:
Write a function is_fib(n)
that returns True if n is a Fibonacci number, and False otherwise.
This is my code:
def is_fib(n):
def fib(x):
if x == 0:
return 0
elif x == 1:
return 1
else:
return fib(x-1) + fib(x-2)
for a in n:
if fib(a) == n:
result = True
break
else:
result = False
return result
Running this give rise to:
TypeError: 'int' object is not iterable.
I have been staring at the code for half an hour. Any help is greatly appreciated.
Upvotes: 1
Views: 1518
Reputation: 101
Firstly thanks to the two guys that helped me. However, for Yoav's edition, python will run into an error when n is a really big number.
This is my new and improved version.
def is_fib(n):
if n < 0:
return False
else:
fib_0 = 0
fib_1 = 1
if n == fib_0 or n == fib_1:
return True
else:
for a in range(2,n+2):
fib = fib_0 + fib_1
fib_0,fib_1 = fib_1,fib
if fib >= n:
break
return fib == n
Upvotes: 0
Reputation: 8041
As jozefg said you are missing range(n)
also notice that you need range(n+2) to cover all cases
def is_fib(n):
def fib(x):
if x == 0:
return 0
elif x == 1:
return 1
else:
return fib(x-1) + fib(x-2)
for a in range(n+2):
if fib(a) == n:
return True
return False
print(is_fib(3))
Upvotes: 0