Python Interview Questions and Answers- Part 3

Answer:

Instance methods are defined inside a class and operate on an instance of that class. They have access to the instance’s attributes and can modify them. Class methods are decorated with @classmethod and operate on the class itself. They have access to the class’s attributes but not the instance’s attributes. Static methods are decorated with @staticmethod and are independent of the class and instance. They do not have access to any instance or class attributes.

Answer:

Python has automatic memory management through garbage collection. However, it’s still possible to have memory leaks when objects are not properly released. To handle memory leaks, you can use tools like profiling and memory debugging, ensure proper object destruction, and avoid unnecessary object references.

Answer:

The __init__ method is a special method in Python classes that is automatically called when a new instance of a class is created. It is used to initialize the attributes and state of the object. It is also known as the constructor method.

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Monkey patching is a practice of modifying or extending existing code at runtime, typically by adding, modifying, or replacing methods or attributes of classes or objects. It can be useful for adding functionality to third-party libraries or fixing issues temporarily, but it can also lead to code complexity and maintenance challenges.

Answer:

Duplicate elements can be removed from a list by converting it to a set and then converting it back to a list. Alternatively, you can use a loop or list comprehension to iterate over the list and keep only the unique elements.

Answer:

A module is a single file encompassing Python code that defines functions, classes, and variables. It can be imported and used in other Python scripts. A package, on the other hand, is a directory that contains multiple Python modules and an additional __init__.py file. The __init__.py file is executed when the package is imported and can be used to define package-level attributes and behavior.

Answer:

Command-line arguments can be handled using the argparse module in Python. It provides a convenient way to parse and validate command-line arguments, define arguments and options, and generate usage messages.

Answer:

Duck typing is a principle in Python in which the suitability of an object is determined by its behavior rather than its specific type or class. If an object supports the required methods or attributes, it can be used in a particular context, regardless of its actual class. This support more flexible and dynamic programming in Python.

Answer:

The else clause in a try statement is executed if no exceptions are raised in the corresponding try block. It is typically used to specify code that should be executed when the try block completes successfully.

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A virtual environment in Python allows you to create isolated Python environments with their own installed packages and dependencies. It can be created using the venv module in Python by running the command python -m venv in the command line.

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A stack can be implemented in Python using a list. Elements can be added to the stack using the append() method, and they can be removed from the stack using the pop() method. The last element in the list represents the top of the stack.

Answer:

The finally clause in a try statement is executed irrespective of whether an exception is raised or not. It is used to specify code that should be executed for cleanup or resource release purposes, ensuring that it is always executed, even if an exception occurs.

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The current working directory can be obtained using the os.getcwd() function from the os module. It returns a string representing the current directory path.

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The ‘with’ statement in Python is used to ensure proper acquisition and release of resources. It is commonly used with file handling, database connections, and other resources. The with statement automatically takes care of releasing the resource, even if an exception occurs.

Answer:

File I/O in Python can be handled using the built-in open() function. It lets you open a file in various modes (read, write, append, etc.), read or write data to the file, and close the file. The with statement is commonly used with file I/O to ensure proper file closure.

Answer:

Specific exceptions can be caught using multiple except blocks, where each block handles a different type of exception. The exceptions are checked in the order they are specified, and the first matching block is executed. For example:

try:

# Code goes here

except ValueError:

# Handle ValueError

except FileNotFoundError:

# Handle FileNotFoundError

except:

# Handle other exceptions

Answer:

Method Resolution Order (MRO) is the order in which Python looks for methods and attributes in a class hierarchy. It determines the precedence of method resolution in multiple inheritance scenarios. The MRO can be viewed using the __mro__ attribute or accessed programmatically using the super() function.

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The __name__ variable is a built-in variable in Python that represents the name of the current module. It is automatically set to “__main__” when the module is run as the main script, and it can be useful to differentiate between being imported as a module or run directly.

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The __str__ method is a special method in Python classes that defines a string representation of an object. It is called by the built-in str() function and is commonly used to provide a human-readable description of the object.

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File handling in Python involves opening files, reading or writing data, and closing files. The open() function is used to open a file, and modes like read (‘r’), write (‘w’), or append (‘a’) can be specified. The read(), write(), and close() methods are used to interact with the file.