What are the most frequently asked advanced Python interview questions ?
Python is an interpreted, interactive, high-level, general-purpose, object-oriented programming language. It supports multiple programming paradigms beyond object-oriented programming.
Python developers are in very high demand as Python has become a solution in many areas.
This blog post shares a list of sample Python interview questions and aswers to help you gauge your readiness.
Let’s take a look at the most frequently asked advanced Python interview questions and answers in technical interviews!?
10+ Advanced Python Interview Questions and Answers
1. What are virtualenvs in Python?
Virtualenv is an isolated environment for developing, running and debugging Python code. It’s used to isolate a Python interpreter with a set of libraries and settings.
Using virtualenv allows you to avoid globally installing Python packages that could break system tools or other projects. You can install virtualenv using pip.
2. What’s the difference between eggs and wheels in Python?
Wheel & Egg are packaging formats that require an installation artifact that does not require compiling or compiling, which is costly in test and production workflows.
Egg format was introduced by setuptools in 2004 and Wheel format was introduced by PEP 427 in 2012.
The wheel is currently built into Python and is considered the standard for binary packaging.
Here are the key differences between Wheel and Egg:
Wheel has an official PEP, while Egg does not.
Moreover, Wheel is a distribution/package format where Egg is both a distribution format and a runtime install format.
Wheel has a richer file naming convention. Additionally, a single wheel archive can demonstrate its compatibility with a number of Python language versions and implementations, ABI, and system architecture.
Wheel is versioned. Each wheel file contains the version of the wheel specification and the application that packaged it.
3. Can you explain Closures?
Closure is a function that has access to a free variable from a surrounding function that completes its execution.
Three features of Python closure are the following:
First, Closure is a nested function,
Second, it has access to a free variable in the outer scope.
Third, it is returned from the surrounding function.
Free variables are variables that are not bound at the local scope. In order for closures to work with immutable variables such as numbers and strings, the nonlocal keyword must be used.
Furthermore, Python closures are used in their decorators.
4. What are metaclasses and when are they used?
Metaprogramming is the potential for a program to have knowledge of or manipulate itself. Additionally, Python supports the metaprogramming format.
Metaclasses are an esoteric OOP concept that hides behind Python code. Therefore, you can use them without realizing it.
The use of custom metaclasses is somewhat controversial, as mentioned in the following quote by the Python guru Tim Peters, who wrote Zen of Python:
“Metaclasses are a deeper magic than 99% of users should worry about. If you’re wondering if you need them, you don’t (the people who really need them know they definitely need them, and they don’t need an explanation for why).”
— Tim Peters
5. Describe compile-time and run-time code checking in Python.
Compile time and runtime are terms that refer to different phases of software program development and include checking a small part during compile time checking.
Compile time converts the code you enter into executable, Runtime is where the executable runs.
Moreover, some of the Python coding is executed at compile time, but all checks are deferred until code execution. If the Python code references a user-defined function that doesn’t exist at all, the code will effectively run. Python code will fail with only one exception when no code execution path is available.
6. How is exception handling in Python different from Java?
Java developers use the try-catch-finally block to perform exception handling.
Python developers, on the other hand, use try and except blocks.
Python exception handles exception handling differently than Java.
But the syntax is similar. In Java an exception is thrown in the code, while Python does not throw an exception, but instead raises the exception.
7. What happens when a function doesn’t have a return statement? Is it valid?
Yes, it is valid. By default, all functions return the specific value of “none” unless an explicit return statement exists to return a value that is not “none”.
If a function doesn’t specify a return value, it returns none. In an if/then conditional statement, none evaluates to false.
8. What is pickling and unpickling in Python?
The python pickle module is used for serializing and deserializing python object structures. Unpickling provides the ability to convert a stream of bytes (generated via pickling) back into python objects in a single operation.
The Python Pickling module enables to convert a class object into a stream of bytes so that it can be stored in a file, also called object serialization.
Use the dump() function for pickling from the pickle module, which returns the brine representation as a byte object instead of writing the object to a file.
Contrarily, Unpickling causes the byte stream to be converted back into a class object, and this is called de-serialization.
Pickling and Unpickling must be done using binaries.
“Pickle is not secure. Only unpickle objects from trusted sources.”
-Python Docs
9. How to use *args and **kwargs in Python?
In Python, a variable number of arguments can be passed to a function with special symbols.
There are 2 symbols used to pass arguments:
1.) *args (Non-Keyword Arguments)
The *args special syntax is used to pass a variable number of arguments to a function.
The syntax is to use the * symbol to take a variable number of arguments.
With *args you can take more arguments than the number of formal arguments you defined earlier and add any number of extra arguments to your existing formal parameters.
2.)**kwargs (Keyword Arguments)
**kwargs are used to pass a variable-length argument list. The reason they’re used with a double star is because they allow the double star to be passed in keyword arguments.
10. If Python is interpreted, what are .pyc files?
The .pyc files are created by the Python interpreter when the .py file is imported.
If the .pyc is newer than the corresponding .py, .pyc files contain the “compiled bytecode” of the imported module/program so that the “translation” from source code to bytecode (which only needs to be done once) can be skipped on subsequent imports. file, thus speeding up startup a bit.
But still. The *.pyc file is interpreted after it is created.
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