PYTHON

 

Python Coding Interview Questions And Answers

1) How do you debug a Python program?

Answer) By using this command we can debug a python program

$ python -m pdb python-script.py

2) What is <Yield> Keyword in Python?

A) The <yield> keyword in Python can turn any function into a generator. Yields work like a standard return keyword.

But it’ll always return a generator object. Also, a function can have multiple calls to the <yield> keyword.

Example:

def testgen(index):
weekdays = ['sun','mon','tue','wed','thu','fri','sat']
yield weekdays[index]
yield weekdays[index+1]
day = testgen(0)
print next(day), next(day)

Output: sun mon

3) How to convert a list into a string?

A) When we want to convert a list into a string, we can use the <”.join()> method which joins all the elements into one and returns as a string.

Example:

weekdays = ['sun','mon','tue','wed','thu','fri','sat']
listAsString = ' '.join(weekdays)
print(listAsString)P

4) How to convert a list into a tuple?

A) By using Python <tuple()> function we can convert a list into a tuple. But we can’t change the list after turning it into tuple, because it becomes immutable.

Example:

weekdays = ['sun','mon','tue','wed','thu','fri','sat']
listAsTuple = tuple(weekdays)
print(listAsTuple)

output: (‘sun’, ‘mon’, ‘tue’, ‘wed’, ‘thu’, ‘fri’, ‘sat’)

5) How to convert a list into a set?

A) User can convert list into set by using <set()> function.

Example:

weekdays = ['sun','mon','tue','wed','thu','fri','sat','sun','tue']
listAsSet = set(weekdays)
print(listAsSet)

output: set([‘wed’, ‘sun’, ‘thu’, ‘tue’, ‘mon’, ‘fri’, ‘sat’])

6) How to count the occurrences of a particular element in the list?

A) In Python list, we can count the occurrences of an individual element by using a <count()> function.

Example # 1:

weekdays = ['sun','mon','tue','wed','thu','fri','sun','mon','mon']
print(weekdays.count('mon'))

Output: 3

Example # 2:

weekdays = ['sun','mon','tue','wed','thu','fri','sun','mon','mon']
print([[x,weekdays.count(x)] for x in set(weekdays)])

output: [[‘wed’, 1], [‘sun’, 2], [‘thu’, 1], [‘tue’, 1], [‘mon’, 3], [‘fri’, 1]]

7) What is NumPy array?

A) NumPy arrays are more flexible then lists in Python. By using NumPy arrays reading and writing items is faster and more efficient.

8) How can you create Empty NumPy Array In Python?

A) We can create Empty NumPy Array in two ways in Python,

1) import numpy
numpy.array([])

2) numpy.empty(shape=(0,0))

9) What is a negative index in Python?

A) Python has a special feature like a negative index in Arrays and Lists. Positive index reads the elements from the starting of an array or list but in the negative index, Python reads elements from the end of an array or list.

10) What is the output of the below code?

>> import array
>>> a = [1, 2, 3]
>>> print a[-3]
>>> print a[-2]
>>> print a[-1]

A) The output is: 3, 2, 1

Advanced Python Coding Interview Questions

11) What is the output of the below program?

>>>names = ['Chris', 'Jack', 'John', 'Daman']
>>>print(names[-1][-1])

A) The output is: n

12) What is Enumerate() Function in Python?

A) The Python enumerate() function adds a counter to an iterable object. enumerate() function can accept sequential indexes starting from zero.

Python Enumerate Example:

subjects = ('Python', 'Interview', 'Questions')
for i, subject in enumerate(subjects):
print(i, subject)

Output:

0 Python
1 Interview
2 Questions

13) What is data type SET in Python and how to work with it?

A) The Python data type “set” is a kind of collection. It has been part of Python since version 2.4. A set contains an unordered collection of unique and immutable objects.

# *** Create a set with strings and perform a search in set

objects = {"python", "coding", "tips", "for", "beginners"}

# Print set.
print(objects)
print(len(objects)) 

# Use of "in" keyword.
if "tips" in objects:
print("These are the best Python coding tips.")

# Use of "not in" keyword.
if "Java tips" not in objects:
print("These are the best Python coding tips not Java tips.")

# ** Output
{'python', 'coding', 'tips', 'for', 'beginners'}
5
These are the best Python coding tips.
These are the best Python coding tips not Java tips.

# *** Lets initialize an empty set
items = set()

# Add three strings.
items.add("Python")
items.add("coding")
items.add("tips") 

print(items)

# ** Output
{'Python', 'coding', 'tips'}

14) How do you Concatenate Strings in Python?

A) We can use ‘+’ to concatenate strings.

Python Concatenating Example:

# See how to use ‘+’ to concatenate strings.

>>> print('Python' + ' Interview' + ' Questions')

# Output:

Python Interview Questions

15) How to generate random numbers in Python?

A) We can generate random numbers using different functions in Python. They are:

#1. random() – This command returns a floating point number, between 0 and 1.

#2. uniform(X, Y) – It returns a floating point number between the values given as X and Y.

#3. randint(X, Y) – This command returns a random integer between the values given as X and Y.

16) How to print sum of the numbers starting from 1 to 100?

A) We can print sum of the numbers starting from 1 to 100 using this code:

print sum(range(1,101))

# In Python the range function does not include the end given. Here it will exclude 101.

# Sum function print sum of the elements of range function, i.e 1 to 100.

17) How do you set a global variable inside a function?

A) Yes, we can use a global variable in other functions by declaring it as global in each function that assigns to it:

globvar = 0
def set_globvar_to_one():
global globvar # Needed to modify global copy of globvar
globvar = 1
def print_globvar():
print globvar # No need for global declaration to read value of globvar
set_globvar_to_one()
print_globvar() # Prints 1

18) What is the output of the program?

names1 = ['Amir', 'Bear', 'Charlton', 'Daman']
names2 = names1
names3 = names1[:]

names2[0] = 'Alice'
names3[1] = 'Bob'

sum = 0
for ls in (names1, names2, names3):
if ls[0] == 'Alice':
sum += 1
if ls[1] == 'Bob':
sum += 10

print sum

A) 12

19) What is the output, Suppose list1 is [1, 3, 2], What is list1 * 2?

A) [1, 3, 2, 1, 3, 2]

20) What is the output when we execute list(“hello”)?

A) [‘h’, ‘e’, ‘l’, ‘l’, ‘o’]

Python Coding Interview Questions And Answers For Experienced

21) Can you write a program to find the average of numbers in a list in Python?

A) Python Program to Calculate Average of Numbers:

n=int(input("Enter the number of elements to be inserted: "))
a=[]
for i in range(0,n):
elem=int(input("Enter element: "))
a.append(elem)
avg=sum(a)/n
print("Average of elements in the list",round(avg,2))

Output:

Enter the number of elements to be inserted: 3
Enter element: 23
Enter element: 45
Enter element: 56
Average of elements in the list 41.33

22) Write a program to reverse a number in Python?

A) Python Program to Reverse a Number:

n=int(input("Enter number: "))
rev=0
while(n>0):
dig=n%10
rev=rev*10+dig
n=n//10
print("The reverse of the number:",rev)

Output:

Enter number: 143
The reverse of the number: 341

23) Write a program to find the sum of the digits of a number in Python?

A) Python Program to Find Sum of the Digits of a Number

n=int(input("Enter a number:"))
tot=0
while(n>0):
dig=n%10
tot=tot+dig
n=n//10
print("The total sum of digits is:",tot)

Output:

Enter a number:1928
The total sum of digits is: 20

24) Write a Python Program to Check if a Number is a Palindrome or not?

A) Python Program to Check if a Number is a Palindrome or Not:

n=int(input("Enter number:"))
temp=n
rev=0
while(n>0):
dig=n%10
rev=rev*10+dig
n=n//10
if(temp==rev):
print("The number is a palindrome!")
else:
print("The number isn't a palindrome!")

Output:

Enter number:151
The number is a palindrome!

25) Write a Python Program to Count the Number of Digits in a Number?

A) Python Program to Count the Number of Digits in a Number:

n=int(input("Enter number:"))
count=0
while(n>0):
count=count+1
n=n//10
print("The number of digits in the number is:",count)

Output:

Enter number:14325
The number of digits in the number is: 5

26) Write a Python Program to Print Table of a Given Number?

A) Python Program to Print Table of a Given Number:

n=int(input("Enter the number to print the tables for:"))
for i in range(1,11):
print(n,"x",i,"=",n*i)

Output:

Enter the number to print the tables for:7
7 x 1 = 7
7 x 2 = 14
7 x 3 = 21
7 x 4 = 28
7 x 5 = 35
7 x 6 = 42
7 x 7 = 49
7 x 8 = 56
7 x 9 = 63
7 x 10 = 70

27) Write a Python Program to Check if a Number is a Prime Number?

A) Python Program to Check if a Number is a Prime Number:

a=int(input("Enter number: "))
k=0
for i in range(2,a//2+1):
if(a%i==0):
k=k+1
if(k<=0):
print("Number is prime")
else:
print("Number isn't prime")

Output:

Enter number: 7
Number is prime

28) Write a Python Program to Check if a Number is an Armstrong Number?

A) Python Program to Check if a Number is an Armstrong Number:

n=int(input("Enter any number: "))
a=list(map(int,str(n)))
b=list(map(lambda x:x**3,a))
if(sum(b)==n):
print("The number is an armstrong number. ")
else:
print("The number isn't an arsmtrong number. ")

Output:

Enter any number: 371
The number is an armstrong number.

29) Write a Python Program to Check if a Number is a Perfect Number?

A) Python Program to Check if a Number is a Perfect Number:

n = int(input("Enter any number: "))
sum1 = 0
for i in range(1, n):
if(n % i == 0):
sum1 = sum1 + i
if (sum1 == n):
print("The number is a Perfect number!")
else:
print("The number is not a Perfect number!")

Output:

Enter any number: 6
The number is a Perfect number!

Python Developer Interview Questions And Answers

30) Write a Python Program to Check if a Number is a Strong Number?

A) Python Program to Check if a Number is a Strong Number:

sum1=0
num=int(input("Enter a number:"))
temp=num
while(num):
i=1
f=1
r=num%10
while(i<=r):
f=f*i
i=i+1
sum1=sum1+f
num=num//10
if(sum1==temp):
print("The number is a strong number")
else:
print("The number is not a strong number")

Output:

Enter a number:145
The number is a strong number.

31) Write a Python Program to Find the Second Largest Number in a List?

A) Python Program to Find the Second Largest Number in a List:

a=[]
n=int(input("Enter number of elements:"))
for i in range(1,n+1):
b=int(input("Enter element:"))
a.append(b)
a.sort()
print("Second largest element is:",a[n-2])

Output:

Enter number of elements:4
Enter element:23
Enter element:56
Enter element:39
Enter element:11
Second largest element is: 39

32) Write a Python Program to Swap the First and Last Value of a List?

A) Python Program to Swap the First and Last Value of a List:

a=[]
n= int(input("Enter the number of elements in list:"))
for x in range(0,n):
element=int(input("Enter element" + str(x+1) + ":"))
a.append(element)
temp=a[0]
a[0]=a[n-1]
a[n-1]=temp
print("New list is:")
print(a)

Output:

Enter the number of elements in list:4
Enter element1:23
Enter element2:45
Enter element3:67
Enter element4:89
New list is:
[89, 45, 67, 23]

33) Write a Python Program to Check if a String is a Palindrome or Not?

A) Python Program to Check if a String is a Palindrome or Not:

string=raw_input("Enter string:")
if(string==string[::-1]):
print("The string is a palindrome")
else:
print("The string isn't a palindrome")

Output:

Enter string: malayalam
The string is a palindrome

34) Write a Python Program to Count the Number of Vowels in a String?

A) Python Program to Count the Number of Vowels in a String:

string=raw_input("Enter string:")
vowels=0
for i in string:
if(i=='a' or i=='e' or i=='i' or i=='o' or i=='u' or i=='A' or i=='E' or i=='I' or i=='O' or i=='U'):
vowels=vowels+1
print("Number of vowels are:")
print(vowels)

Output:

Enter string: Hello world
Number of vowels are: 3

35) Write a Python Program to Check Common Letters in Two Input Strings?

A) Python Program to Check Common Letters in Two Input Strings:

s1=raw_input("Enter first string:")
s2=raw_input("Enter second string:")
a=list(set(s1)&set(s2))
print("The common letters are:")
for i in a:
print(i)

Output:

Enter first string:Hello
Enter second string:How are you
The common letters are:
H
e
o