Python Interview Questions

Python is a programming language with objects, modules, threads, exceptions, and automatic memory management.

PEP 8 is a coding convention, a set of recommendations, about how to write your Python code more readable.

The pickle module accepts any Python object and converts it into a string representation and dumps it into a file by using the dump function, this process is called pickling. While the process of retrieving original Python objects from the stored string representation is called unpickling.

Python language is an interpreted language. Python program runs directly from the source code. It converts the source code that is written by the programmer into an intermediate language, which is again translated into machine language that has to be executed.

• Python memory is managed by Python private heap space. All Python objects and data structures are located in a private heap. The programmer does not have an access to this private heap and the interpreter takes care of this Python private heap.
• The allocation of Python heap space for Python objects is done by the Python memory manager. The core API gives access to some tools for the programmer to code.
• Python also has an inbuilt garbage collector, which recycles all the unused memory and frees the memory, and makes it available to the heap space.

PyChecker is a static analysis tool that detects the bugs in Python source code and warns about the style and complexity of the bug. Pylint is another tool that verifies whether the module meets the coding standard.

A Python decorator is a specific change that we make in Python syntax to alter functions easily.

The difference between list and tuple is that list is mutable while the tuple is not. Tuple can be hashed for e.g as a key for dictionaries.

Everything in Python is an object and all variables hold references to the objects. The reference values are according to the functions; as a result, you cannot change the value of the references. However, you can change the objects if it is mutable.

They are syntax constructions to ease the creation of a Dictionary or List based on existing iterable.

There are mutable and Immutable types of Pythons built-in types Mutable built-in types

• List
• Sets
• Dictionaries

Immutable built-in types

• Strings
• Tuples
• Numbers

In Python, every name introduced has a place where it lives and can be hooked for. This is known as namespace. It is like a box where a variable name is mapped to the object placed. Whenever the variable is searched out, this box will be searched, to get the corresponding object.

It is a single expression anonymous function often used as inline function.

A lambda form in python does not have statements as it is used to make new function object and then return them at runtime.

Pass means, no-operation Python statement, or in other words, it is a place holder in the compound statement, where there should be a blank left and nothing has to be written there.

In Python, iterators are used to iterate a group of elements, containers like a list.

A unit testing framework in Python is known as unittest. It supports sharing of setups, automation testing, shutdown code for tests, aggregation of tests into collections, etc.

A mechanism to select a range of items from sequence types like list, tuple, strings, etc. is known as slicing.

The way of implementing iterators is known as generators. It is a normal function except that it yields expression in the function.

A Python documentation string is known as docstring, it is a way of documenting Python functions, modules, and classes.

To copy an object in Python, you can try copy.copy () or copy.deepcopy() for the general case. You cannot copy all objects but most of them.

Python sequences can be index in positive and negative numbers. For the positive index, 0 is the first index, 1 is the second index, and so forth. For the negative index, (-1) is the last index and (-2) is the second last index, and so forth.

In order to convert a number into a string, use the inbuilt function str(). If you want an octal or hexadecimal representation, use the inbuilt function oct() or hex().

Xrange returns the range object while range returns the list, and uses the same memory and no matter what the range size is.

In Python, the module is the way to structure a program. Each Python program file is a module, which imports other modules like objects and attributes.

The folder of the Python program is a package of modules. A package can have modules or subfolders.

Local variables: If a variable is assigned a new value anywhere within the function's body, it's assumed to be local.

Global variables: Those variables that are only referenced inside a function are implicitly global.

To share global variables across modules within a single program, create a special module. Import the config module into all modules of your application. The module will be available as a global variable across modules.

To make a Python Script executable on Unix, you need to do two things,

• Script file's mode must be executable and
• the first line must begin with # ( #!/usr/local/bin/python)

By using a command os.remove (filename) or os.unlink(filename)

To generate random numbers in Python, you need to import command as

import random

random.random()

This returns a random floating-point number in the range [0,1)

You can access a module written in Python from C by following method,

Module = =PyImport_ImportModule("");

It is a Floor Divisionoperator, which is used for dividing two operands with the result as quotient showing only digits before the decimal point. For instance, 10//5 = 2 and 10.0//5.0 = 2.0.

• Python comprises a huge standard library for most Internet platforms like Email, HTML, etc.
• Python does not require explicit memory management as the interpreter itself allocates the memory to new variables and free them automatically
• Provide easy readability due to the use of square brackets
• Easy-to-learn for beginners
• Having the built-in data types saves programming time and effort from declaring variables

The use of the split function in Python is that it breaks a string into shorter strings using the defined separator. It gives a list of all words present in the string.

Flask is a web microframework for Python based on "Werkzeug, Jinja 2 and good intentions" BSD licensed. Werkzeug and jinja are two of their dependencies.

Flask is part of the micro-framework. Which means it will have little to no dependencies on external libraries. It makes the framework light while there is a little dependency to update and fewer security bugs.