Python Q&A
Python Q&A - Part3
93) What is a variable?
Answer: Variable is used to store data
94) How to change global variable inside function?
Answer: Use the global keyword
95) What are the values of x and y?
x = 10;y = 20
def fn():
global x
x = 30
y=40
fn()
print(‘x is:’,x)
print(‘y is:’,y)
Answer: x is 30 and y is 20
96) What is the output of the following?
l=lambda n: n*n
print(l(8))
Answer: 64
97) What is the output of the following?
l=lambda n1,n2:n1*n2
print(l(8,5))
Answer: 40
98) How are anonymous functions defined?
Answer: Using the lambda keyword
99) How many arguments can lambda have?
Answer: Lambda can have any number of arguments
100) How many expressions can lambda have?
Answer: Lambda can have one expression
101) How is lambda generally used in Python?
Answer: As an argument to a higher-order function
102) print(‘1’ + ‘2’)
Answer: 12
103) print(1+2)
Answer: 3
104) What is a filter?
Answer: Filters filters the iterable with help of function
105) What are the parameters of filter?
Answer: Function and iterable
106) What is the output of the following?
lst=[2,3,4,5,6,7,8]
def fn(n):
if n%2==0:
return True
lst1=filter(fn,lst)
for x in lst1:
print(x)
Answer: 2,4,6,8
107) Dump the list [‘a’,’b’,’c’] to a file using json
Answer:
lst=[‘a’,’b’,’c’]
import json
str=json.dumps(lst)
file1 = open(“C:\\Test\\file1.txt”,’w’)
json.dump(lst,file1)
108) print(float(“2”))
Answer: 2.0
109) Is Set a mutable data type?
Answer: Yes
110) Does Set have ordered values?
Answer: No
111) Does Set have duplicate values?
Answer: No
112) Write code with map() function to square the numbers in the list
lst=[2,3,4]
Answer:
lst=[2,3,4]
def fn(n):
return n*n
lst1=map(fn,lst)
for x in lst1:
print(x)
113) What is map()
Answer: Map processes items in an iterable
114) Which is faster Map() or loop()?
Answer: Map is faster
115) What is difference between map and filter?
Answer: Map transforms elements in iterable, while filter removes elements in the iterable
116) What is difference between list and tuple?
Answer: Lists are mutable, while tuples are immutable
117) How should an identifier begin?
Answer: Character A-Z or a-z or underscore
118) Is python case sensitive
Answer: Yes
119) How can you display all members of object?
Answer: dir()
120) What does keys() do?
Answer: Gets list of keys in dictionary
121) How can you retrieve part of list or tuple?
Answer: Using slicing
122) What is isalnum()?
Answer: Checks if characters in string are alphanumeric
123) What does this do?
import os
print(os.getcwd())
Answer: Prints the current working directory path
124) lst=[9,8,7,6]
print(lst[::-1])
Answer: [6, 7, 8, 9]
125) print(max(‘Python’))
Answer: y
126) print(complex(1,2))
Answer: (1+2j)
127) How do you get data from keyboard?
Answer:
Use input().
Input(“What is your name:”)
128) print(1>2 and 2>1)
Answer: false
129) print(1>2 or 2>1)
Answer: true
130) print(not 1>2 and 2>1)
Answer: true
131) print(‘trend’ in ‘Python is trend’)
Answer: true
132) print(‘trend’ not in ‘Python is trend’)
Answer: false
133) What is recursion?
Answer: A function calling itself is recursion
134) print([x for x in range(1,7)])
Answer: [1, 2, 3, 4, 5, 6]
135) print([x for x in range(1,7,2)])
Answer: [1, 3, 5]
136) What is the use of inheritance?
Answer: Provides code reusability and it is transitive
137) How many types of inheritance in Python?
Answer: 4 types of inheritance in Python
138) What is single inheritance?
Answer: Derived class inherits from single parent class
139) What is multiple inheritance?
Answer: Derived class inherit from more than 1 base class
140) What is multi-level inheritance?
Answer: Base, derived classes inherit to new derived class
141) What is hierarchical inheritance?
Answer: Create more than 1 derived class from single base
142) What are Python libraries?
Answer: They are a collection of Python packages
143) Give some examples of Python libraries
Answer: Numpy, Pandas,Matplotlib etc