Python Interview Questions – Set 02

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What is Pass in Python?

Pass specifies a Python statement without operations. It is a placeholder in a compound statement. If we want to create an empty class or functions, this pass keyword helps to pass the control without error.

# For Example
class Student:
pass # Passing class
class Student:
def info():
pass # Passing function

How can you convert a number to string?

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

Why do we use join() function in Python?

The join() is defined as a string method which returns a string value. It is concatenated with the elements of an iterable. It provides a flexible way to concatenate the strings. See an example below.

str = “Rohan”
str2 = “ab”
# Calling function
str2 = str.join(str2)
# Displaying result
print(str2)
Output:

aRohanb

What are the differences between Python 2.x and Python 3.x?

Python 2.x is an older version of Python. Python 3.x is newer and latest version. Python 2.x is legacy now. Python 3.x is the present and future of this language.

The most visible difference between Python2 and Python3 is in print statement (function). In Python 2, it looks like print “Hello”, and in Python 3, it is print (“Hello”).

String in Python2 is ASCII implicitly, and in Python3 it is Unicode.

The xrange() method has removed from Python 3 version. A new keyword as is introduced in Error handling.

What is Python?

Python was created by Guido van Rossum, and released in 1991.

It is a general-purpose computer programming language. It is a high-level, object-oriented language which can run equally on different platforms such as Windows, Linux, UNIX, and Macintosh. It is widely used in data science, machine learning and artificial intelligence domain.

It is easy to learn and require less code to develop the applications.

It is widely used for:

  • Web development (server-side).
  • Software development.
  • Mathematics.
  • System scripting.

Why Python?

  • Python is compatible with different platforms like Windows, Mac, Linux, Raspberry Pi, etc.
  • Python has a simple syntax as compared to other languages.
  • Python allows a developer to write programs with fewer lines than some other programming languages.
  • Python runs on an interpreter system, means that the code can be executed as soon as it is written. It helps to provide a
  • prototype very quickly.
  • Python can be described as a procedural way, an object-orientated way or a functional way.

What are the rules for a local and global variable in Python?

In Python, variables that are only referenced inside a function are called implicitly global. If a variable is assigned a new value anywhere within the function’s body, it’s assumed to be a local. If a variable is ever assigned a new value inside the function, the variable is implicitly local, and we need to declare it as ‘global’ explicitly. To make a variable globally, we need to declare it by using global keyword. Local variables are accessible within local body only. Global variables are accessible anywhere in the program, and any function can access and modify its value.

What will be the output of data[-2] from the list data = [1,5,8,6,9,3,4]?

In the list, an element present at the 2nd index from the right is 3. So, the output will be 3.

What is zip() function in Python?

Python zip() function returns a zip object, which maps a similar index of multiple containers. It takes an iterable, convert into iterator and aggregates the elements based on iterables passed. It returns an iterator of tuples.

Signature

zip(iterator1, iterator2, iterator3 …)
Parameters

iterator1, iterator2, iterator3: These are iterator objects that are joined together.

Return

It returns an iterator from two or more iterators.

Explain docstring in Python?

The Python docstring is a string literal that occurs as the first statement in a module, function, class, or method definition. It provides a convenient way to associate the documentation.

String literals occurring immediately after a simple assignment at the top are called “attribute docstrings”.

String literals occurring immediately after another docstring are called “additional docstrings”.

Python uses triple quotes to create docstrings even though the string fits on one line.

Docstring phrase ends with a period (.) and can be multiple lines. It may consist of spaces and other special chars.

Example

# One-line docstrings
def hello():
“””A function to greet.”””
return “hello”

Give an example of shuffle() method?

This method shuffles the given string or an array. It randomizes the items in the array. This method is present in the random module. So, we need to import it and then we can call the function. It shuffles elements each time when the function calls and produces different output.

import random

list = [12,25,15,65,58,14,5,];
print(list)
random.shuffle(list)
print (“Reshuffled list : n”, list)
[12, 25, 15, 65, 58, 14, 5]
Reshuffled list :
[58, 15, 5, 65, 12, 14, 25]