HackerRank - Map and Lambda Function Solution

Let's learn some new Python concepts! You have to generate a list of the first N fibonacci numbers, 0 being the first number. Then, apply the map function and a lambda expression to cube each fibonacci number and print the list.

Concept

The map() function applies a function to every member of an iterable and returns the result. It takes two parameters: first, the function that is to be applied and secondly, the iterables.
Let's say you are given a list of names, and you have to print a list that contains the length of each name.

>> print (list(map(len, ['Tina', 'Raj', 'Tom'])))  
[4, 3, 3]  

Lambda is a single expression anonymous function often used as an inline function. In simple words, it is a function that has only one line in its body. It proves very handy in functional and GUI programming.

>> sum = lambda a, b, c: a + b + c
>> sum(1, 2, 3)
6

Note:

Lambda functions cannot use the return statement and can only have a single expression. Unlike def, which creates a function and assigns it a name, lambda creates a function and returns the function itself. Lambda can be used inside lists and dictionaries.

Input Format

One line of input: an integer N.

Constraints

Output Format

A list on a single line containing the cubes of the first N fibonacci numbers.

Sample Input

5

Sample Output

[0, 1, 1, 8, 27]

Explanation

The first  fibonacci numbers are [0, 1, 1, 2, 3], and their cubes are [0, 1, 1, 8, 27].

Solution in Python3

    
    cube = lambda x: x**3

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

    if __name__ == '__main__':
        n = int(input())
        print(list(map(cube, fibonacci(n))))