Online Ethical Hacking Course

Apply Now

Examples

Python Program for Fibonacci Series (Print Fibonacci Sequence in Python)

Let’s learn how to write a program to print Fibonacci series in Python with examples and proper explanations. Whether you're a beginner in programming or an experienced coder, understanding and implementing the Fibonacci series program in Python is a fundamental skill for you.

The Fibonacci series is a sequence of numbers where each number is the sum of the two preceding ones. This series has fascinated mathematicians, scientists, and programmers alike due to its intriguing patterns and widespread applications in various fields, such as mathematics, computer science, and even nature.

Here, we will explore different techniques to generate the Fibonacci series in Python. We will delve into various approaches, including the use of while loops, for loops, recursion, iteration, and even lambda functions.

So, get ready to expand your programming knowledge with Python program for Fibonacci series. 

Fibonacci Series Program in Python

Code

# Fibonacci Series in Python Using While Loop

def fibonacci_series(n):
    series = []
    a, b = 0, 1

    while len(series) < n:
        series.append(a)
        a, b = b, a + b

    return series

# Test the program
number = int(input("Enter the number of terms: "))
fib_series = fibonacci_series(number)
print("Fibonacci Series:")
print(fib_series)

Output

Enter the number of terms: 6
Fibonacci Series:
[0, 1, 1, 2, 3, 5]

Explanation

  • We define a function fibonacci_series(n) that takes an integer n as input and returns a list containing the Fibonacci series of n terms.

  • We initialize an empty list series to store the Fibonacci series. We also initialize two variables a and b to 0 and 1, respectively. These variables represent the current and next terms of the series.

  • Using a while loop, we continue generating Fibonacci numbers until the length of the series list reaches the desired number of terms (n). Inside the loop, we append the current Fibonacci number (a) to the series list and update a and b by assigning b to a + b and a to b, respectively. This ensures that we generate the next number in the Fibonacci sequence.

  • Finally, we return the list containing the Fibonacci series.

  • To test the program, we prompt the user to enter the number of terms they want in the Fibonacci series. We then call the fibonacci_series() function, passing the user's input as an argument, and store the resulting Fibonacci series in the fib_series variable. 

  • Finally, we print the Fibonacci series to the console.

Python Course

Fibonacci Series Program in Python Using for loop

Code

# Python program for Fibonacci series

def fibonacci_series(n):
    series = [0, 1]

    for i in range(2, n):
        series.append(series[i-1] + series[i-2])

    return series

# Test the program
number = int(input("Enter the number of terms: "))
fib_series = fibonacci_series(number)
print("Fibonacci Series:")
print(fib_series)

Output

Enter the number of terms: 12
Fibonacci Series:
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89]

Explanation

  • We define a function fibonacci_series(n) that takes an integer n as input and returns a list containing the Fibonacci series of n terms.

  • We initialize the series list with the first two Fibonacci numbers, 0 and 1.

  • Using a for loop, we iterate from 2 to n-1. Inside the loop, we append the sum of the previous two Fibonacci numbers (series[i-1] and series[i-2]) to the series list.

  • Finally, we return the series list containing the Fibonacci series.

  • To test the program, we prompt the user to enter the number of terms they want in the Fibonacci series. We then call the fibonacci_series() function, passing the user's input as an argument, and store the resulting Fibonacci series in the fib_series variable. 

  • Finally, we print the Fibonacci series to the console.

nth Fibonacci Number in Python

Code

# Using recursion to print fibonacci sequence in Python

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

# Test the program
number = int(input("Enter the value of n: "))
fib_number = fibonacci_recursive(number)
print("The", number, "th Fibonacci number is:", fib_number)

Output

Enter the value of n: 25
The 25 th Fibonacci number is: 75025

Explanation

  • We define a function fibonacci_recursive(n) that calculates the nth Fibonacci number using recursion. 

  • If the input n is less than or equal to 1, we return n as it is the base case. Otherwise, we recursively call the fibonacci_recursive() function for n-1 and n-2, summing their results to find the nth Fibonacci number.

Fibonacci Series Program in Python Using Recursion

Code

# Python program for Fibonacci series using recursion

def fibonacci_series(n):
    if n <= 0:
        return []
    elif n == 1:
        return [0]
    elif n == 2:
        return [0, 1]
    else:
        series = fibonacci_series(n-1)
        series.append(series[-1] + series[-2])
        return series

# Test the program
number = int(input("Enter the number of terms: "))
fib_series = fibonacci_series(number)
print("Fibonacci Series:")
print(fib_series)

Output

Enter the number of terms: 15
Fibonacci Series:
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377]

Explanation

We define a function fibonacci_series(n) that takes an integer n as input and returns a list containing the Fibonacci series of n terms.

The function uses a recursive approach to generate the Fibonacci series. We define three base cases:

  • If n is less than or equal to 0, an empty list is returned.

  • If n is equal to 1, a list containing only the first Fibonacci number, 0, is returned.

  • If n is equal to 2, a list containing the first two Fibonacci numbers, 0 and 1, is returned.

For n greater than 2, we call the fibonacci_series() function recursively, passing n-1 as the argument. We store the result in the series variable.

To generate the next Fibonacci number, we append the sum of the last two numbers in the series list (series[-1] and series[-2]) to the series list.

Finally, we return the series list containing the Fibonacci series

Fibonacci Series in Python Using Iteration

Code

# Program for Fibonacci sequence in Python

def fibonacci_series(n):
    series = [0, 1]

    if n <= 2:
        return series[:n]

    for i in range(2, n):
        series.append(series[i-1] + series[i-2])

    return series

# Test the program
number = int(input("Enter the number of terms: "))
fib_series = fibonacci_series(number)
print("Fibonacci Series:")
print(fib_series)

Output

Enter the number of terms: 8
Fibonacci Series:
[0, 1, 1, 2, 3, 5, 8, 13]

Explanation

  • We define a function fibonacci_series(n) that takes an integer n as input and returns a list containing the Fibonacci series of n terms.

  • We initialize the series list with the first two Fibonacci numbers, 0 and 1.

  • If the requested number of terms (n) is less than or equal to 2, we return a slice of the series list that contains the appropriate number of terms. This avoids unnecessary iterations in such cases.

  • For n greater than 2, we use a for loop that iterates from 2 to n-1. Inside the loop, we calculate the next Fibonacci number by summing the previous two numbers (series[i-1] and series[i-2]) and append it to the series list.

  • Finally, we return the series list containing the Fibonacci series.

Practice More Python Programs:

Useful Python Resources:

Python Program for Fibonacci Series: Video