I would use this method:

Python 2

a = int(raw_input('Give amount: ')) def fib(n): a, b = 0, 1 for _ in xrange(n): yield a a, b = b, a + b print list(fib(a)) 

Python 3

a = int(input('Give amount: ')) def fib(n): a, b = 0, 1 for _ in range(n): yield a a, b = b, a + b print(list(fib(a))) 

You are giving a too many meanings:

a = int(raw_input('Give amount: ')) 

vs.

a = fib() 

You won't run into the problem (as often) if you give your variables more descriptive names (3 different uses of the name a in 10 lines of code!):

amount = int(raw_input('Give amount: ')) 

and change range(a) to range(amount).

Since you are writing a generator, why not use two yields, to save doing the extra shuffle?

import itertools as it num_iterations = int(raw_input('How many? ')) def fib(): a,b = 0,1 while True: yield a b = a+b yield b a = a+b for x in it.islice(fib(), num_iterations): print x 

.....

Really simple with generator:

def fin(n): a, b = 0, 1 for i in range(n): yield a a, b = b, a + b ln = int(input('How long? ')) print(list(fin(ln))) # [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...] 

Python is a dynamically typed language. the type of a variable is determined at runtime and it can vary as the execution is in progress. Here at first, you have declared a to hold an integer type and later you have assigned a function to it and so its type now became a function.

you are trying to apply 'a' as an argument to range() function which expects an int arg but you have in effect provided a function variable as argument.

the corrected code should be

 a = int(raw_input('Give amount: ')) def fib(): a, b = 0, 1 while 1: yield a a, b = b, a + b b = fib() b.next() for i in range(a): print b.next(), 

this will work

def fibonacci(n): fn = [0, 1,] for i in range(2, n): fn.append(fn[i-1] + fn[i-2]) return fn 

To get the fibonacci numbers till any number (100 in this case) with generator, you can do this.

def getFibonacci(): a, b = 0, 1 while True: yield b b = a + b a = b - a for num in getFibonacci(): if num > 100: break print(num) 

def genFibanocciSeries(): a=0 b=1 for x in range(1,10): yield a a,b = b, a+b for fib_series in genFibanocciSeries(): print(fib_series) 

Your a is a global name so-to-say.

a = int(raw_input('Give amount: ')) 

Whenever Python sees an a, it thinks you are talking about the above one. Calling it something else (elsewhere or here) should help.

Also you can use enumerate infinite generator:

for i,f in enumerate(fib()): print i, f if i>=n: break 

Also you can try the closed form solution (no guarantees for very large values of n due to rounding/overflow errors):

 root5 = pow(5, 0.5) ratio = (1 + root5)/2 def fib(n): return int((pow(ratio, n) - pow(1 - ratio, n))/root5) 

You had the right idea and a very elegant solution, all you need to do fix is your swapping and adding statement of a and b. Your yield statement should go after your swap as well

a, b = b, a + b #### should be a,b = a+b,a #####

`###yield a` 

Simple way to print Fibonacci series till n number

def Fib(n): i=a=0 b=1 while i<n: print (a) i=i+1 c=a+b a=b b=c Fib(input("Please Enter the number to get fibonacci series of the Number : ")) 

a = 3 #raw_input def fib_gen(): a, b = 0, 1 while 1: yield a a, b = b, a + b fs = fib_gen() next(fs) for i in range(a): print (next(fs)) 

I recently discovered this type of construct (many thanks to @KellyBundy for this), so I couldn't resist:

n = 20 fib = (a for a,b in [(0,1)] for _ in range(n) for a,b in [(b,a+b)]) print(list(fib)) # [1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765] 

I've build this a while ago:

a = int(raw_input('Give amount: ')) fab = [0, 1, 1] def fab_gen(): while True: fab.append(fab[-1] + fab[-2]) yield fab[-4] fg = fab_gen() for i in range(a): print(fg.next()) 

No that fab will grow over time, so it isn't a perfect solution.

It looks like you are using the a twice. Try changing that to a different variable name.

The following seems to be working great for me.

def fib(): a, b = 0, 1 while True: yield a a, b = b, a+b f = fib() for x in range(100): print(f.next()) 

i like this version:

array = [0,1] for i in range(20): x = array[0]+array[1] print(x) array[0] = array[1] array[1] = x 

Below are two solution for fiboncci generation:

def fib_generator(num): ''' this will works as generator function and take yield into account. ''' assert num > 0 a, b = 1, 1 while num > 0: yield a a, b = b, a+b num -= 1 times = int(input('Enter the number for fib generaton: ')) fib_gen = fib_generator(times) while(times > 0): print(next(fib_gen)) times = times - 1 def fib_series(num): ''' it collects entires series and then print it. ''' assert num > 0 series = [] a, b = 1, 1 while num > 0: series.append(a) a, b = b, a+b num -= 1 print(series) times = int(input('Enter the number for fib generaton: ')) fib_series(times) 

Why do you go for complex here is one of my snippet to work on!!

n = int(input('Enter your number..: ')) a = 0 b = 1 c = 0 print(a) print(b) for i in range(3, n+1): c = a+b print(c) a,b=b,c 

check out my git - rohith-sreedharan

Write the following code:

nterm = int(input("How many Fibonacci numbers do you want to find out? ")) n1 = 0 n2 = 1 fibonacciList = [ n1, n2 ] if nterm >= 1: for i in range(nterm): fibonacciList.insert( len(fibonacciList), fibonacciList[-1] + fibonacciList[-2] ) print(fibonacciList[0:len(fibonacciList) - 2]) else: print("Invalid value") 

len means length.

;

I need to make a program that asks for the amount of Fibonacci numbers printed and then prints them like 0, 1, 1, 2... but I can't get it to work. My code looks the following:

Since noone answered directly to your code...

>>> def fib(): ... a,b = 0,1 ... while True: ... yield a ... # for code clarity I've spit, maybe someone is learning ... a=b ... b= a+b ... # renamed 'a' to 'gen' to not confuse with 'a' and 'b' in function. for code readability >>> gen = fib() # we assign generator to variable (so we wont re-run it >>> next(gen) # you had a.next() or gen.next() this is not a method of generator, # it is built-in in python for iterators 0 >>> next(gen) 1 >>> next(gen) 2 >>> next(gen) 4 >>> next(gen) 8 >>> next(gen) 16 

... and so on... of course you can acreate a loop if you want :)

We can use it in a short way without through 'yield and 'next' statements

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