Daily Coding Problem #5

Problem:

cons(a, b) constructs a pair, and car(pair) and cdr(pair) returns the first and last element of that pair. For example, car(cons(3, 4)) returns 3, and cdr(cons(3, 4)) returns 4.

 

Given this implementation of cons:

def cons(a, b):
    def pair(f):
        return f(a, b)
    return pair

Implement car and cdr.

 

-Summary-

def car(pair):
    def return_first(a, b):
        return a
    return pair(return_first)

def cdr(pair):
    def return_last(a, b):
        return b
    return pair(return_last)

이번문제를 풀면서 python closures 라는 개념에 대해 배웠다.

https://www.learnpython.org/en/Closures#:~:text=A%20Closure%20is%20a%20function,variables%20of%20the%20enclosing%20scope.

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