Top 60 Python Interview Questions and Answers
1. Who developed the
Python?
Python was initially
designed by Guido Van Rossum in 1991 and developed by Python Software
Foundation.
2. Python is which type
of programming language?
Python is an
object-oriented programming language.
3. What are the main features of Python?
- Python is very easy to learn
- It is an interpreter based language
- Dynamic and versatile language
- Lots of libraries are there for programmers
- It is an object-oriented language that supports all the
features of OOP’s and for this reason, we can build any kind of
application.
4. What is the
difference between interactive mode and script mode in Python?
When the user runs one
single line code or one block of code then it is Interactive mode and the user runs
a set of lines as a block then it is called script mode.
5 . What do you mean by
IDLE in Python?
IDLE is Integrated
Development Environment for editing and running Python programs. It is
installed with a Python interpreter. It has a number of features to help
programmers to develop python code with powerful syntax.
6. What are the benefits
of Python?
Python is a very
easy-to-learn language and we can do all kinds of programs including data
science, artificial intelligence, data analytics with the help of different
libraries. It is also open source so we can do the thing according to our own
ease and use it to our advantage.
7. Can keywords be used
as identifiers?
No, keywords can not be
used as identifiers or variables.
8. Write down the
available token in Python.
- Identifier
- Punctuator
- Keywords
- Literals
- Operators
9 . What do mean by
Rvalue and Lvalue?
- Rvalue: Pulls or fetches the value stored in a variable
or constant.
- Lvalue: It is usually an identifier or variable where
value assign.
10 . Python is
dynamically typed. Explain it.
A dynamically typed
language is associated with run-time values and not named variables. So as a
programmer we can write a little quicker because you do not have to specify
types every time. Python does not know about the type of the variable until the
code is run, that is why the declaration is not used. It stores the value at
the same memory location and then binds that variable name to that memory
location or container.
10. How is memory
managed in Python?
Python memory manager handled the memory management. The Python
memory manager allocates the memory in the form of private heap space. All the
objects are stored in heap memory and it is not accessible to the programmer.
Python provides some APIs to work with heap memory. Above all python has to build a Garbage collection to clear out unused space.
11. What is the
difference between a module and a package in Python?
A module in Python is a file containing a set of methods whereas a package in python provides the
programmer with the application development tools (API) by providing a hierarchical directory structure in which sub-package and modules contain.
12. What is PEP 8?
The PEP 8(Python Enhancement Proposal) is defined as documentation
that helps us to give the guidelines on how to write the Python code. Guido van
Rossum, Barry Warsaw, and Nick Coghlan in 2001 were the writers of PEP8.
It is for the improvement and readability of Python code.
13. What are the built-in types available
in Python?
There are six built-in
types available in Python, which are as follows
The mutable types:
1. List
2. Sets
3. Dictionaries
The immutable types:
1. Tuples
2. Strings
3. Numbers
14. Explain the difference between a list and a
tuple?
- Both are heterogeneous types but the list is mutable
and a tuple is immutable.
- List declare in square brackets and Tuple declare in
parenthesis ().
15. What is String?
A sequence of characters
is known as String. String is immutable
16. What is the difference between /, //, and %
operators?
/ Operator is used to
find quotient while % operator is used to finding reminder and // is used
for integer division (Quotient).
17. What is the difference between = and == operators?
The single equal to ‘=’
is the assignment operator and ‘==’ is the equality (Relation operator) operator
18. What is an identity operator?
Identity operators in
Python is used to determine whether a value is of a certain class or type.
19. What is a String
replication operator?
The star sign ‘*’ is a
string replication operator and it is used print string repetitively as follows
St=’Hello ’
Print(st * 3)
Output
Hello Hello Hello
20. What do you mean by
debugging?
It is a process by which
we remove errors from the program and make it bug-free.
21. How many types of
compile-time errors?
There are two
compile-time types error
- First is Syntax Error
- Second Semantic Error
22. Difference between
testing and debugging.
Debugging is the process
of correcting errors in a program and testing is the process to find the error
23. what do mean by list
in Python?
The list is a data
structure that is a type container and it stores multiple data (heterogeneous
data) at the same time. It is mutable.
22. What is traversing a
list?
Traversing a list is a
technique to access an individual element of a list.
23. What is the use of
the list() method?
The List() method has
converted a sequence like a tuple into the list.
24. What is the difference
between the remove() and pop() function in python?
The remove() method
removes the given data from the list and the pop() method deletes the data from the
list by the given index.
25. What do you mean by
membership operators in Python?
The membership operator
are of two types
‘in’ operator and ‘not
in’ operator
And it is used to check
whether a value or variable exists in the sequence or not like say list as
follows
Li = [3, 5, 6, 7, 8]
Print(3 in Li) – It will
give true because 3 is there in the list if not then it will print false.
26. What is Packing and Unpacking in Python tuple?
In packing, we put data
into a new tuple while in unpacking we extract those values into a single
variable.
For example
Tup = (60, 70, ‘Hi’,
‘Bye’, 89)
a, b, c, d, e = Tup
print(a) will print 60
print(b) will print 70
print(c) will print Hi
etc
27. What is a dictionary?
A dictionary in python
is an order collection of data that stores key and value as an element and { } the bracket is used for it.
For example
Dict1 = {1 : ’Koma’, 2 :
‘Kamal’, 3 : ‘Sachine}
28. How many ways are there to iterate over a dictionary?
There are three ways to
iterate over a dictionary as
- Iterate through all keys
- Iterate through all values
- Iterate through all keys and values
28. What is the scope of
a variable?
The scope of a variable
refers to the part of the module or function where it can be used. A variable
can be global or local scope.
29. What is the Pickle module?
This module is used for serializing and de-serializing a Python object structure. This module serializes the first before writing data to file. Pickling is a way to convert a python object such as dict, list, tuple into a character stream and then save it to the disk.
30. What is Python Anonymous/ Lambda Function?
The
nameless property function is called a lambda function or anonymous. It is used to create a new method object and
return them at runtime.
function.Syntax of lambda function:
lambda:
argument_list:expression
Add 20 to
argument a, and return the result:
x
= lambda a : a + 20
print(x(5))
Ans: 25
31. What are decorators in Python?
A decorator in python is a function that changes a specific syntax for the easy alteration of functions basically it adds functionalities to an existing function, object, or code without modifying its structure permanently
32. What is the difference between generators and
iterators?
Iterator is used in python to iterate over a group of
elements such as list, tuple.
For example
li = [2, 4, 5, 6, 8]
iterator = iter(li)
print(next (iterator))
print(next (iterator))
print(next (iterator))
In python, a generator is an exceptional type of function which does not return a single value, instead, it returns an iterator
object with a sequence of values. A yield statement is used instead
of a return statement. The following is a simple generator function.
For example
def printValue():
for i
in range(20):
if (i % 2 == 0):
yield i
# Function call using for loop
for i in printValue():
print(i, end=' ')
output : 0 2 4 6 8
10 12 14 16 18
All the even number is
printed.
33. What is the range() function and what are its
parameters?
The
Python range() the function is to generate a sequence of numbers starting
from the given start integer to the stop integer. A range is a built-in function object is generally used for a loop.
Syntax
range(start, stop[, step])
start: It is the
starting position, generally, it starts from zero (0)
stop: Stop position
step: Specify the increment value
# Generate numbers
between 0 to 10
for i in range(10):
print(i, end=' ')
Output : 0 1 2 3 4 5 6 7
8 9
# Generate even numbers
between 2 to 18
for i in range(2, 20, 2):
print(i, end=' ')
Output: 2 4 6 8 10 12 14
16 18
35. What is the zip() function in Python?
The
zip() function in Python returns a zip object, which combines the contents
of two or more iterables. It returns an iterator of tuples. Actually,
it accepts iterable items and merges them into a single tuple.
36. How do garbage collection in python?
The garbage collection in Python is
automatic means it allocation and de-allocation method is automatic. The user
does not have to do pre-allocate or de-allocate memory as it is used in C or C++.
Python has two strategies for memory allocation:
- Reference counting
- Garbage collection
37. Is Python an object-oriented language?
Yes, Python is an object-oriented language. An object-oriented language using classes and objects
38. What is a class and an object in Python?
Class is a blueprint of an object and an object is an instance of a class.
39. What is a constructor and its usage?
A constructor is a function and it is called or executes automatically when an object is being created.
The main usage of the constructor is to declare and initialize
instance variables. __init()__ method is called the constructor in Python.
In other words, the name of the constructor should be __init__(self).
40. How many types of constructors are there?
There are two types of constructors in Python.
- Non-parameterized: This is called default too. The Python constructors in which have no parameter are known as non-parameterized constructors. The no parameterized constructor uses when we do not want to just initialize the instance variable and it has self.
- Parameterized Constructor:
The Python constructor which has parameters is known as a parameterized
constructor. The parameterized constructor has multiple parameters along with
the
self.
41. What is PYTHONPATH?
Python provides PYTHONPATH which is used to add different directories
when a module or package is imported. The Python interpreter uses PYTHONPATH to
determine which module to load.
42. What is the difference between Python arrays and lists?
- Both Array and List store data. But an array containing elements of the same data type and list contains different data types.
- The array is homogenous whereas List is Heterogeneous
- Array consumes less memory than the list.
- From left to right or we can say positive index starts from zero (0) and that index runs till n-1.
- And negative index start from -1 and second is -2 and so on and starts from right to left.
44. What is docstring?
It
is a documentation string. We define docstring with triple single quotes or
triple double quotes. It is a multiple lines string. If we want to define a multi-line document in a variable then we have to create a docstring.
Example
docstr="""Python
is a modern programming Language
It is a
very easy language to learn
We can
do different types of program
It is an
object-oriented language
"""
print(docstr)
45. What is the difference between .pyc and .py files?
- .pyc is a bytecode file whereas the .py file is a Python source file.
- .pyc is loaded before .py files and save the time to re-compile
46. How can you generate random numbers in Python?
Python Random module is used to generate a random number. The
method is defined as:
import random
r=random.randint(3, 6)
print(r)
seq = (20, 24, 87, 75, 78, 30, 38, 87, 88)
r=random.choice(seq)
print(r)
Output:
3
75
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