Day_12.md

Question 44

Question:

Write a program which can map() to make a list whose elements are square of numbers between 1 and 20 (both included).

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Hints:

Use map() to generate a list. Use lambda to define anonymous functions.

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Main Author's Solution: Python 2

squaredNumbers = map(lambda x: x**2, range(1,21))
print squaredNumbers

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My Solution: Python 3

def sqr(x):
    return x*x

squaredNumbers = list(map(sqr, range(1,21)))
print (squaredNumbers)

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Question 45

Question:

Define a class named American which has a static method called printNationality.

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Hints:

Use @staticmethod decorator to define class static method.There are also two more methods.To know more, go to this link.

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Main Author's Solution: Python 2

class American(object):
    @staticmethod
    def printNationality():
        print "America"

anAmerican = American()
anAmerican.printNationality()
American.printNationality()

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My Solution: Python 3

class American():
    @staticmethod
    def printNationality():
        print("I am American")

american = American()
american.printNationality()   # this will not run if @staticmethod does not decorates the function.
                              # Because the class has no instance.

American.printNationality()   # this will run even though the @staticmethod
                              # does not decorate printNationality()

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Question 46

Question:

Define a class named American and its subclass NewYorker.

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Hints:

Use class Subclass(ParentClass) to define a subclass.*

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Main Author's Solution: Python 2

class American(object):
    pass

class NewYorker(American):
    pass

anAmerican = American()
aNewYorker = NewYorker()
print anAmerican
print aNewYorker

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My Solution: Python 3

class American():
    pass

class NewYorker(American):
    pass

american = American()
newyorker = NewYorker()

print(american)
print(newyorker)

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