PCPP-32-101 Questions and Answers
Question # 1
Select the true statement about composition
A.
Composition extends a class's capabilities by adding new components and modifying the existing ones.
B.
Composition allows a class to be projected as a container of different classes
C.
Composition is a concept that promotes code reusability while inheritance promotes encapsulation.
D.
Composition is based on the has a relation: so it cannot be used together with inheritance.
Answer:
B
Explanation:
Explanation:
Composition is an object-oriented design concept that models a has-a relationship. In composition, a class known as composite contains an object of another class known as component. In other words, a composite class has a component of another class1.
B. Composition allows a class to be projected as a container of different classes.
Composition is a concept in Python that allows for building complex objects out of simpler objects, by aggregating one or more objects of another class as attributes. The objects that are aggregated are generally considered to be parts of the whole object, and the containing object is often viewed as a container for the smaller objects.
In composition, objects are combined in a way that allows for greater flexibility and modifiability than what inheritance can offer. With composition, it is possible to create new objects by combining existing objects, by using a container object to host other objects. By contrast, with inheritance, new objects extend the behavior of their parent classes, and are limited by that inheritance hierarchy.
References:
- Official Python documentation on Composition:Â https://docs.python.org/3/tutorial/classes.html#composition
- GeeksforGeeks article on Composition vs Inheritance:Â https://www.geeksforgeeks.org/composition-vs-inheritance-python/
- Real Python article on Composition and Inheritance:Â https://realpython.com/inheritance-composition-python/
Question # 2
Analyze the code and choose the best statement that describes it.
A.
___ne___() is not a built-in special method
B.
The code is erroneous
C.
The code is responsible for the support of the negation operator e.g. a = - a.
D.
The code is responsible for the support of the inequality operator i.e. i =
Answer:
D
Explanation:
Explanation:
The correct answer is D. The code is responsible for the support of the inequality operator i.e. i != j. In the given code snippet, the __ne__ method is a special method that overrides the behavior of the inequality operator != for instances of the MyClass class. When the inequality operator is used to compare two instances of MyClass, the __ne__ method is called to determine whether the two instances are unequal.
Question # 3
Select the true statements related to PEP 8 programming recommendations for code writing. (Select two answers:)
A.
You should use the not ... is operator (e.g. if not spam is None:), rather than the is not operator (e.g.if spam is notNone:), to increase readability.
B.
You should make object type comparisons using the ismstanceQ method (e.g. if isinstance (obj, int) :) instead of comparing types directly (eg if type(obj) is type(i)).
C.
You should write code in a way that favors the CPython implementation over PyPy, Cython. and Jython.
D.
You should not write string literals that rely on significant trailing whitespaces as they may be visually indistinguishable, and certain editors may trim them
Answer:
B, D
Explanation:
Explanation:
The two true statements related to PEP 8 programming recommendations for code writing are Option B and Option D.
Option B is true because PEP 8 recommends making object type comparisons using the isinstance() method instead of comparing types directly 1.
Option D is true because PEP 8 recommends not writing string literals that rely on significant trailing whitespaces as they may be visually indistinguishable, and certain editors may trim them 1.
