Python Interview Q&A

Introduction

This page contains a list of typical Python Interview Questions and Answers.

Python Interview Questions

These questions and answers cover some fundamental Python concepts that are often discussed in interviews.

• A variable created inside a function belongs to the local scope of that function, and can only be used inside that function.
• A variable created in the main body of the Python code is a global variable and belongs to the global scope. Global variables are available from within any scope, global and local.

• An iterator is an object that contains a countable number of values.
• An iterator is an object that can be iterated upon, meaning that you can traverse through all the values.
• Technically, in Python, an iterator is an object which implements the iterator protocol, which consist of the methods __iter__() and __next__().

• All classes in Python have a function called __init__(), which is always executed when the class is being initiated.
• We can use the __init__() function to assign values to object properties, or other operations that are necessary to do when the object is being created.

• Use lambda functions when an anonymous function is required for a short period of time.

Lists, tuples, and sets are all used to store multiple items in a single variable, but they have different properties:

• A list is ordered and changeable. It allows duplicate values.
• A tuple is ordered but unchangeable (immutable). It also allows duplicates.
• A set is unordered, unindexed, and contains only unique items. It is changeable, but you cannot modify individual elements by index.

• You can use the isalnum() method, which returns True if all the characters are alphanumeric, meaning alphabet letter (a-z) and numbers (0-9).

• You can use the int() function, like this:

• Indentation refers to the spaces at the beginning of a code line. Where in other programming languages the indentation in code is for readability only, the indentation in Python is very important.
• Python uses indentation to indicate a block of code.
• Python will give you an error if you skip the indentation.

• SET

• Inheritance allows us to define a class that inherits all the methods and properties from another class.
• Parent class is the class being inherited from, also called base class.
• Child class is the class that inherits from another class, also called derived class.

• Above ten, and also above 20!

• Text Type: str
• Numeric Types: int, float, complex
• Sequence Types: list, tuple, range
• Mapping Type: dict
• Set Types: set, frozenset
• Boolean Type: bool
• Binary Types: bytes, bytearray, memoryview

• Membership operators are used to test if a sequence is present in an object. The in and not in operators are examples of these:

• The pass statement

• Arbitrary Arguments are often shortened to *args in Python documentations.
• If you do not know how many arguments that will be passed into your function, add a * before the parameter name in the function definition. This way the function will receive a tuple of arguments, and can access the items accordingly.

• To create a module just save the code you want in a file with the file extension .py: def greeting(name):  print("Hello, " + name)
• Now we can use the module we just created, by using the import statement: import mymodulemymodule.greeting("Jonathan")

• No, because: list2 will only be a reference to list1, and changes made in list1 will automatically also be made in list2.
• To make a copy of a list, you can use copy() or the list() method.

• You can return a range of characters by using the "slice syntax".
• Specify the start index and the end index, separated by a colon, to return a part of the string, for example:

• A Class is like an object constructor, or a "blueprint" for creating objects.
• You can create a class with the class keyword: class MyClass: x = 5 Now we can use the class named MyClass to create objects: Create an object named p1, and print the value of x: p1 = MyClass() print(p1.x)