Find fibonacci series upto n using lambda in Python

A Fibonacci series is a widely known mathematical sequence that explains many natural phenomena. It starts with 0 and 1, then each subsequent term is the sum of the two preceding terms. In this article, we will see how to generate a given number of Fibonacci terms using lambda functions in Python.

Method 1: Using map() with Lambda

We use the map() function to apply a lambda function that adds the sum of the last two terms to our list. The any() function is used to execute the map operation ?

Example

def fibonacci(count):
    fib_list = [0, 1]
    
    any(map(lambda _: fib_list.append(sum(fib_list[-2:])), 
            range(2, count)))
    
    return fib_list[:count]

print(fibonacci(8))
print(fibonacci(5))

The output of the above code is ?

[0, 1, 1, 2, 3, 5, 8, 13]
[0, 1, 1, 2, 3]

Method 2: Using reduce() with Lambda

The reduce() function applies a lambda function cumulatively to build the Fibonacci sequence. This approach uses functional programming principles ?

Example

from functools import reduce

fib_numbers = lambda n: reduce(lambda x, _: x + [x[-1] + x[-2]], 
                              range(n - 2), [0, 1])

print(fib_numbers(8))
print(fib_numbers(10))

The output of the above code is ?

[0, 1, 1, 2, 3, 5, 8, 13]
[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]

How It Works

Both methods use lambda functions to generate Fibonacci numbers:

• Method 1: Uses map() with any() to repeatedly append new terms
• Method 2: Uses reduce() to build the sequence step by step

Comparison

Conclusion

Both lambda-based approaches effectively generate Fibonacci sequences. The map() method is more readable, while reduce() follows pure functional programming principles. Choose based on your preference for readability versus functional style.