The Python Programming Language Quiz

Quiz Answer Key and Fun Facts

1. Which of these is a Python control flow statement type?

Answer: elif

Pythonic control flow statements are if, elif, and else. It lacks a switch-case statement, which is why programmers can only use the if/else paradigm for control flow. The basic syntax is:

if condition:
some_statement_1
elif other_condition:
some_statement_2
else:
some_statement_3

The only mandatory statement is 'if'. 'elif' and 'else' are optional, and are used when there are multiple conditions. One control flow block can have a maximum of one 'if' statement, and one 'else' statement with any number of 'elif' in between.

2. Which of these structures does not exist in Python?

Answer: Array

Believe it or not, Python does not have a natively built array structure! Instead, lists and tuples are used as substitutes. Lists are a more general implementation of arrays, with the key difference between the two being that lists are mutable and type-independent.

This means that you can store elements of different types in an array, and you can increase or decrease the size of the array without having to explicitly declare it. Tuples are immutable, but also type-independent.

3. We start writing a program to compute the square of the first n numbers, where n is a number to be input by the user. But unfortunately, we do not have the ability to store the list in memory! Which of these functions would I use to bypass this constraint?

Answer: Generator

Generators are extremely useful in Python because they are lazily computed, meaning that once a generator is created, the user can obtain the next value by simply iterating over it. Generators save us huge amounts of memory, and are generally used when the entire collection of numbers isn't needed at once.

4. How would I decorate a class method if I wanted to use it without initializing a class?

Answer: @staticmethod

Static methods should be used sparingly, but can be used without initializing their parent class. They do not receive an implicit first method, which is why they can be used without initializing a class. Conversely, undecorated class methods always take 'self' as their first method, referring to the class itself. If an undecorated method is called without initializing a class, the self argument will not be found because there is no instance of the class.

5. Since lists are mutable, which of these methods would I use to add an element to the list?

Answer: append

The append method is used to add elements to a list. It takes only one argument, the element to add to the list. However, this argument is type independent, and you can also add dictionaries, class instances, tuples and other lists to a list.

6. Suppose we wanted to use a function A from library B, where A is a top-level function. Which of these is the correct way to import *only* A?

Answer: from B import A

The only keywords you can use to import a library are 'from', 'as' and 'import'. 'import' specifically adds the library to your namespace, whereas 'from B import A' adds A to your namespace. They both have their uses, but if you want to use only a specific function A, it is considered better practice to use 'from...import', and if you want to use multiple methods from the library, you can use 'import B'. 'as' is used to alias.

For example, if you're import library verylongname, you can alias it as 'v', and in the rest of the code, the interpreter will understand that you are using the verylongname library if you use 'v'.

7. Which of these simple functions reverses a string, which is set to the variable a?

Answer: a[::-1]

.reverse() and .invert() are not string methods, which leaves the two string splicing methods. a[:-1] retrieves the last character of the string, whereas you can reverse the entire string by using a[::-1]. String splicing in general is very easy and versatile with Python.

8. What does Python's 'set' data structure do?

Answer: Returns an unordered collection of unique elements

Python's 'set' data structure allows you to obtain every single unique element in a list, and filter out the duplicates. For example, a set of the list [0,0,1,2] would be [0,1,2].

9. Sometimes while performing file input/output, programmers forget to close the file, leading to errors and corrupted data. Which of the following can we do to prevent this?

Answer: Perform all file operations inside a 'with' block

A 'with' block is the most Pythonic way to perform file operations. It involves no extra overhead, and automatically closes the file at the end of the block. Open files can lead to memory clogging and corrupted data, and the 'with' block makes the code more manageable.

10. When we run our code, we keep getting an error and our code stops running. Which one of these keyword pairs can we use to catch the error and bypass it to keep the code running?

Answer: try...except

A try...except block works by trying to perform whatever is coded inside 'try'. If it comes across any error specified in the except block, the code in the except block will be run and the routine will continue. If the code runs into an error not specified in the except block, the routine will be terminated.

Source: Author lordingtar

This quiz was reviewed by FunTrivia editor WesleyCrusher before going online.
Any errors found in FunTrivia content are routinely corrected through our feedback system.

Python, created by Guido van Rossum, is one of the most versatile programming languages today. It is widely used in web programming and known for its massive collection of user libraries.

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