# How to Implement the Fibonacci Sequence in Python

09/10/2021

Contents

In this article, you will learn how to implement the fibonacci sequence in Python.

## The Fibonacci Sequence in Python

There are several ways to implement the Fibonacci sequence in Python, here are three common ones:

#### Using a loop:

This method uses a loop to calculate the nth term of the Fibonacci sequence.

```
def fibonacci(n):
if n <= 0:
return 0
elif n == 1:
return 1
else:
fib = [0, 1]
for i in range(2, n + 1):
fib.append(fib[i - 1] + fib[i - 2])
return fib[n]
```

#### Using recursion:

This method uses recursion to calculate the nth term.

```
def fibonacci(n):
if n <= 0:
return 0
elif n == 1:
return 1
else:
return fibonacci(n - 1) + fibonacci(n - 2)
```

#### Using dynamic programming:

The third method uses dynamic programming, which is a more efficient approach compared to recursion, as it stores the values of already calculated terms in a dictionary memo to avoid unnecessary recalculations.

```
def fibonacci(n, memo={}):
if n <= 0:
return 0
elif n == 1:
return 1
elif n in memo:
return memo[n]
else:
memo[n] = fibonacci(n - 1, memo) + fibonacci(n - 2, memo)
return memo[n]
```