Top 11 Python Interview Questions

There are many high-level programming languages; however, Python language gain increased popularity among cybersecurity professionals in recent years for many reasons like:

1. Python programming is considerably easy to learn, comparable with Java and C, and its syntax is much simpler.

2. Python is a free and open-source programming language so that anyone can play with its code.

3. Python is supported by a very large community of developers worldwide. Cybersecurity professionals can find many ready code snippets and a wide range of libraries to use in their programs.

4. Python can aid in many cybersecurity functions such as reverse engineering, automating repetitive tasks (such as harvesting data from the web), network scanning, malware analysis, and penetration testing.

Many security projects are accomplished using Python programming, such as:

• Web server fingerprinting
• Cyberattacks simulation (creating custom scripts and tools to perform various cyberattacks)
• Port scanning
• Websites mirroring
• Testing load balancing of a website
• Creating intrusion detection and prevention systems
• Network scanning
• Automating tasks like applying the same security template on hundreds of endpoint devices.

Python has witnessed enormous growth in demand, and there is no sign of slowing down soon. According to PYPL, the Python programming language was ranked number one until March 2021.

This article will discuss popular python questions that you can expect to have during a python interview.

Top 11 Python programming interview questions

Question 1: What are the key features of Python?

• Python is an interpreted language. Hence, it does not need to be compiled first before running it. You can execute python programs directly after installing the python interpreter.
• Python is dynamically typed: You do not need to define variable type before using it; Python will detect its type automatically. For example: x = 11 python will interpret variable x as integer.
• Python is an object-oriented language; hence you can define classes and subclasses as any other OOP language such as Java and C.
• Although writing Python programs is quick, it is slower than other compiled languages such as Java.

Question 2: What do you mean by “Python is an interpreted language.”?

You do not need to compile Python code into machine language first before running them.

Question 3: What is the purpose of the PYTHONPATH environment variable?

PYTHONPATH environment variable instructs Python interpreter where to locate the module files imported into a program. It is used to add additional directories that Python search for custom Python libraries.

Question 4: What data types are supported in Python?

Python supports five standard data types: Numbers, Strings, Lists, Tuples, and Dictionaries.

Question 5: What are Python modules? Name some popular built-in Python modules.

A module is a Python file (has py extension) with arbitrarily named attributes. A module can define classes, functions, and variables and may contain running code. Some popular built-in Python modules are os, sys, math, random, datetime, and json.

Question 6: What are local variables and global variables in Python?

Global variables are declared outside a function scope, and any functions across the program can use them. Example of a global variable (see Figure 1). Figure 1 - Declaring Global variables in Python

Local variables are declared inside a Python function or a local scope (see Figure 2). Figure 2 - Python local variable

Question 7: Explain type conversion in Python?

Type conversion is referred to the conversion of one object data type into another data type. For example: converting an integer into a string. Some Python built-in functions for data conversion include:

int() – converts any data type into integer type float() – converts into float type ord() – converts characters into integer hex() – converts integers to hexadecimal oct() – converts integer to octal tuple() – convert to a tuple list() – convert any data type to a list type dict() – convert a tuple of order (key-value) into a dictionary str() – convert an integer into a string

Question 8: Write a simple program to sort a numerical list in Python.

See Figure 3. Figure 3 - Sort a numerical list in Python

Question 9: What is a lambda function?

Lambda is an anonymous function that can take many arguments but can have only one statement.

Question 10: Explain Inheritance in Python?

Inheritance allows one class to inherit all attributes and functions of another class. The inheritance provides the following benefits for Python programs:

• It represents real-world relationships between a parent and child class.
• It provides code reusability.
• Inheritance is a transitive relationship; if class B inherits from parent class A, then all the subclasses of B would automatically inherit from class A.

Superclass (also known as parent class) is the one being inherited from.

Child class (also known as sub or derived class) is the class that inherits from another class.

Python support four types of inheritance:

• Single Inheritance
• Multi-level inheritance
• Hierarchical inheritance
• Multiple inheritances

Unlike Java, Python supports multi-inheritance when one class inherits the properties and methods from more than one parent class.

Question 11: How does Python manage memory?

Python memory is managed via private heap space. All Python objects are stored in a private heap which the Python interpreter itself manages. Programmers cannot access the private heap.

Python built-in garbage collector is responsible for freeing all unused memory so that private heap space can allocate memory again.

Summary

Python programming language is a must-learn for any security professional wanting to advance their career. Many penetrations testing and digital forensics tools are written using Python. Python also helps IT professionals automate numerous repetitive tasks such as network scanning and applying security templates on all devices connected to the same network.