HackerRank Python Solution - Functionals - Map and Lambda Function

Let's learn some new Python concepts! You have to generate a list of the first 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 second, 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:

• 0 <= N <= 15

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:

cube = lambda x: x**3 # complete the lambda function 

def fibonacci(n):
    # return a list of fibonacci numbers
    count,n1 = 0,0
    n2 =1
    ans = []
    
    while count < n:
        ans.append(n1)
        nth = n1 + n2
        # update the new values 
        n1, n2 = n2, nth
        count += 1
    return ans

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