Fibonacci numbers python, what should i learn to be a better programmer (self taught )

Question

n1 = 0
n2 = 1
fiblist = []
while True:     
     newNum = n1 + n2
     fiblist.append(newNum)
     n1 = n2
     n2 = newNum
     if newNum >= 10000:
          print(flist)
          break

beginner programmer: is there an easier way to write this or some other more effective way

In python, variables and functions are name `lowercase_with_underscores` not `camelCase` — Boris Verkhovskiy, Dec 02 '19 at 03:10
[Many code examples for Fibonacci](https://rosettacode.org/wiki/Fibonacci_sequence#Python) in Python and other programming languages. — DarrylG, Dec 02 '19 at 03:14
May I recommend https://codereview.stackexchange.com/ for open-ended questions about the quality of your code, like this one? Stack Overflow is more suitable for specific questions. — kaya3, Dec 02 '19 at 04:25

DarrylG · Answer 1 · 2019-12-02T13:25:24.723

Your code can be simplified to the following.

fiblist = [0, 1]                # initialize with first two numbers
while fiblist[-1] < 10000:      # while last number <= threshold
  fiblist.append(fiblist[-1] + fiblist[-2])  # next is sum of last 2 numbers

print(fiblist)

Explanation (provided since you asked for things to learn to be a better coder)

Simplification of your code to above based upon principles from two references

Style guide: Python Style Guide
Python Mantra: Zen of Python

Using reference 1

PEP 8 Guide: "Function names should be lowercase, with words separated by underscores as necessary to improve readability". This is Python-specific. Other languages (i.e. C++, Java, Clojure, JavaScript, etc.) have their own preferred styles. So for Python: new_num rather than newNum (i.e. not camelCase for variables and function names).

Using reference 2

Zen of Python: "Simple is better than complex".

Your while loop is overly complicated by focusing on two objectives, namely: (1) generating fibonacci numbers, and (2) printing fibonacci numbers). From Single Repository Principle we know less is better than more (i.e. objectives).

Simplify by creating code blocks with single rather than multiple objectives.

while True:                # objective 1--generating fib numbers
     newNum = n1 + n2
     fiblist.append(newNum)
     n1 = n2
     n2 = newNum
     if newNum >= 10000:
          break

print(fiblist)             # objective 2--printing fib numbers

Next, we simplify by improving robustness. Robustness — "Simple objects allow you to focus on the specificities of each task individually and reduces the amount of input/output variables you need to consider at any given time". fiblist is a simple object we can use to replace n1, n2, and new_num as follows:

fiblist[-2] is n1
fiblist[-1] is n2
fiblist[-1] is new_num (after append)

Using robustness the code becomes:

while fiblist[-1] < 10000:
    fiblist.append(fiblist[-1] + fiblist[-2])

In order for this to work, we need to initialize fiblist before the while loop to:

fiblist = [0, 1]

Thus with this sequence of simplifications, we obtain the suggested code.

Additional References to be a better Programmer

score 0 · Answer 2 · answered Dec 02 '19 at 03:55

use generators or iterators in python to generate a series than creating a list.
python simplifies swapping variables as a, b = b , a

def fibanocci(n1, n2, size):
    for i in range(size):
        yield n1
        n1, n2 = n2, n1 + n2

Now to use the series,

>>> for i in fibanocci(1, 1, 5):
...     print(i)
... 
1
1
2
3
5
>>>

Fibonacci numbers python, what should i learn to be a better programmer (self taught )

2 Answers2