Tutorial Playlist
200 Lessons1. Introduction to Python
2. Features of Python
3. How to install python in windows
4. How to Install Python on macOS
5. Install Python on Linux
6. Hello World Program in Python
7. Python Variables
8. Global Variable in Python
9. Python Keywords and Identifiers
10. Assert Keyword in Python
Now Reading
11. Comments in Python
12. Escape Sequence in Python
13. Print In Python
14. Python-if-else-statement
15. Python for Loop
16. Nested for loop in Python
17. While Loop in Python
18. Python’s do-while Loop
19. Break in Python
20. Break Pass and Continue Statement in Python
21. Python Try Except
22. Data Types in Python
23. Float in Python
24. String Methods Python
25. List in Python
26. List Methods in Python
27. Tuples in Python
28. Dictionary in Python
29. Set in Python
30. Operators in Python
31. Boolean Operators in Python
32. Arithmetic Operators in Python
33. Assignment Operator in Python
34. Bitwise operators in Python
35. Identity Operator in Python
36. Operator Precedence in Python
37. Functions in Python
38. Lambda and Anonymous Function in Python
39. Range Function in Python
40. len() Function in Python
41. How to Use Lambda Functions in Python?
42. Random Function in Python
43. Python __init__() Function
44. String Split function in Python
45. Round function in Python
46. Find Function in Python
47. How to Call a Function in Python?
48. Python Functions Scope
49. Method Overloading in Python
50. Method Overriding in Python
51. Static Method in Python
52. Python List Index Method
53. Python Modules
54. Math Module in Python
55. Module and Package in Python
56. OS module in Python
57. Python Packages
58. OOPs Concepts in Python
59. Class in Python
60. Abstract Class in Python
61. Object in Python
62. Constructor in Python
63. Inheritance in Python
64. Multiple Inheritance in Python
65. Encapsulation in Python
66. Data Abstraction in Python
67. Opening and closing files in Python
68. How to open JSON file in Python
69. Read CSV Files in Python
70. How to Read a File in Python
71. How to Open a File in Python?
72. Python Write to File
73. JSON Python
74. Python JSON – How to Convert a String to JSON
75. Python JSON Encoding and Decoding
76. Exception Handling in Python
77. Recursion in Python
78. Python Decorators
79. Python Threading
80. Multithreading in Python
81. Multiprocеssing in Python
82. Python Regular Expressions
83. Enumerate() in Python
84. Map in Python
85. Filter in Python
86. Eval in Python
87. Difference Between List, Tuple, Set, and Dictionary in Python
88. List to String in Python
89. Linked List in Python
90. Length of list in Python
91. Reverse a List in Python
92. Python List remove() Method
93. How to Add Elements in a List in Python
94. How to Reverse a List in Python?
95. Difference Between List and Tuple in Python
96. List Slicing in Python
97. Sort in Python
98. Merge Sort in Python
99. Selection Sort in Python
100. Sort Array in Python
101. Sort Dictionary by Value in Python
102. Datetime Python
103. Random Number in Python
104. 2D Array in Python
105. Abs in Python
106. Advantages of Python
107. Anagram Program in Python
108. Append in Python
109. Applications of Python
110. Armstrong Number in Python
111. Assert in Python
112. Binary Search in Python
113. Binary to Decimal in Python
114. Bool in Python
115. Calculator Program in Python
116. chr in Python
117. Control Flow Statements in Python
118. Convert String to Datetime Python
119. Count in python
120. Counter in Python
121. Data Visualization in Python
122. Datetime in Python
123. Extend in Python
124. F-string in Python
125. Fibonacci Series in Python
126. Format in Python
127. GCD of Two Numbers in Python
128. How to Become a Python Developer
129. How to Run Python Program
130. In Which Year Was the Python Language Developed?
131. Indentation in Python
132. Index in Python
133. Interface in Python
134. Is Python Case Sensitive?
135. Isalpha in Python
136. Isinstance() in Python
137. Iterator in Python
138. Join in Python
139. Leap Year Program in Python
140. Lexicographical Order in Python
141. Literals in Python
142. Matplotlib
143. Matrix Multiplication in Python
144. Memory Management in Python
145. Modulus in Python
146. Mutable and Immutable in Python
147. Namespace and Scope in Python
148. OpenCV Python
149. Operator Overloading in Python
150. ord in Python
151. Palindrome in Python
152. Pass in Python
153. Pattern Program in Python
154. Perfect Number in Python
155. Permutation and Combination in Python
156. Prime Number Program in Python
157. Python Arrays
158. Python Automation Projects Ideas
159. Python Frameworks
160. Python Graphical User Interface GUI
161. Python IDE
162. Python input and output
163. Python Installation on Windows
164. Python Object-Oriented Programming
165. Python PIP
166. Python Seaborn
167. Python Slicing
168. type() function in Python
169. Queue in Python
170. Replace in Python
171. Reverse a Number in Python
172. Reverse a string in Python
173. Reverse String in Python
174. Stack in Python
175. scikit-learn
176. Selenium with Python
177. Self in Python
178. Sleep in Python
179. Speech Recognition in Python
180. Split in Python
181. Square Root in Python
182. String Comparison in Python
183. String Formatting in Python
184. String Slicing in Python
185. Strip in Python
186. Subprocess in Python
187. Substring in Python
188. Sum of Digits of a Number in Python
189. Sum of n Natural Numbers in Python
190. Sum of Prime Numbers in Python
191. Switch Case in Python
192. Python Program to Transpose a Matrix
193. Type Casting in Python
194. What are Lists in Python?
195. Ways to Define a Block of Code
196. What is Pygame
197. Why Python is Interpreted Language?
198. XOR in Python
199. Yield in Python
200. Zip in Python
Python's assert keyword is an effective testing and debugging utility. It enables programmers to validate assumptions and verify particular conditions within code. When an assertion is made, Python evaluates the expression following the "assert" keyword. This article provides an in-depth understanding of the assert keyword in Python using examples and code illustrations.
Assert keyword in Python example 1:
x = “good”
assert x == “good”
#the statement is true, and therefore nothing happens
assert x == “bad”
#the statement is false and shows an assertion error.
The assert keyword in Python is used for several reasons. Additionally, the Python assert in production code serves many benefits. The usefulness of the assert keyword in Python can be understood by the example below:
Example 2:
def divide(a, b):
assert b != 0, "Error: Division by zero!"
return a / b
numerator = 10
denominator = 0
result = divide(numerator, denominator)
print(result)
Explanation: The assert statement checks whether the denominator is not equal to zero (b !=0). The assert statement returns False since the denominator is set to 0, and the code shows an assertion error with the message “Error: Division by zero!"
The assert Python 3 is mainly used for debugging codes. You can use it when you want to ensure that the conditions embedded in your code are satisfied.
Example 3:
x = “red”
assert x == “pink”, “x should be ‘red’”
In the above example, the assert function checks whether the variable x has an input string “pink.” Since x has already been defined as “red,” the assert returns False, and the code displays the following assertion error, “x should be ‘red.’”
In a tedious code, the assert statement is important to avoid the mistake of inserting unspecified conditions in your code. This ensures that your code runs error-free.
In Python, the assert keyword is easy to understand due to its simple execution. The code below depicts the assert keyword in a Python example.
Example 4:
def check_even_number(num):
assert num % 2 == 0, "Number is not even!"
print("Number is even.")
Trial 1: check_even_number(4)
Output: The number is even
Trial 2: check_even_number(7)
Output: The number is not even!
Explanation:
It is easy to comprehend the working of this statement from the flowchart given below:
When an "AssertionError" is raised in Python, the normal implementation of the program is interrupted, and its progress is halted. This error indicates that an assertion statement failed, meaning the assertion's condition was evaluated as False.
The assert keyword in Python follows a simple format. This is given by:
assert condition, error_message (optional)
Example 5:
a=10
b=2
assert b!=0, “error: division by zero”
print(“result”, a/b)
Here, assert b!=0 is an assert condition that checks whether b (denominator) is not equal to zero. In case it is zero, the error_message (error: division by zero) is displayed.
The assert keyword in Python need not have an error message. The error message is optional. The following example shows how the error message is not really needed while inserting an assert keyword in a program.
Example 6:
# initializing number
a = 7
b = 0
# using assert to check for 0
print("The value of a / b is : ")
assert b != 0
print(a / b)
Output: Assertion error:
The assert statement detects that the condition is false and raises an assertion error Python. Since the error is not specified, the output doesn’t specify the error too.
The assert keyword in Python goes well with an error message. Python asserts with a message is good because:
Example 7:
def calculate_average(numbers):
assert len(numbers) > 0, "Error: List is empty!"
average = sum(numbers) / len(numbers)
return average
empty_data = []
result = calculate_average(empty_data)
print(f"The average is: {result}")
Output: “Error: List is empty!"
Assert inside a function is used within a function’s code. It serves the same property as before i.e. checking for the validity of assumptions and conditions. It also ensures that specific conditions hold true at any point during the execution of the function.
Example 8:
The code below comprises a function for calculating the discounted price from the original price by asserting the value of the discount percentage in the range [0,100].
def calculate_discounted_price(original_price, discount):
assert discount >= 0 and discount <= 100, "Invalid discount percentage!"
discounted_price = original_price - (original_price * (discount / 100))
return discounted_price
#trial
price = 1000
discount_percentage = 120
final_price = calculate_discounted_price(price, discount_percentage)
print(f"The final price after a {discount_percentage}% discount is: ${final_price}")
Output "Invalid discount percentage!"
Since the discount percentage is set to 120, the assert statements return false, and the program fails by showing the error message.
The assert keyword in Python takes the boolean expression as its argument, returning either false or true. The example can understand this:
def check_positive_number(num):
assert num > 0, "Number should be positive!"
print("Number is positive.")
# Trial and output
check_positive_number(5) # Valid positive number
check_positive_number(-2) # Invalid positive number
The assert keyword in Python is not a variable. It is just a keyword. This is because:
Asserting dictionary values in Python involves verifying the veracity or validity of specific dictionary values. This can be accomplished by combining the "assert" statement with dictionary access and comparison operations
Example:
person = {
'name': 'John,'
'age': 30,
'country': 'USA'
}
assert person['name'] == 'John', "Incorrect name value"
assert person['age'] >= 18, "Age should be 18 or greater"
assert person['country'] in ['USA,' 'Canada'], "Invalid country"
print("All dictionary values are valid.")
In practical terms, the keyword "assert" assists with the following:
The assert keyword in Python is essential for various reasons in the programming languages. The different syntax for assert statements enables the user to verify the conditions and assumptions included in the code. However, it is important to remember that assert in Python is a keyword, not a variable type.
Q1. Should assert be used?
Assert should be used for debugging and testing code.
Q2. What is the result of assert in Python?
The assert raises an error if the false value is returned.
Q3. What is the difference between try-except and assert?
Try and except blocks are used for handling exceptions. The assert is used for verifying conditions for the function.
PAVAN VADAPALLI
Director of Engineering
Director of Engineering @ upGrad. Motivated to leverage technology to solve problems. Seasoned leader for startups and fast moving orgs. Working …Read More
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upGrad does not grant credit; credits are granted, accepted or transferred at the sole discretion of the relevant educational institution offering the diploma or degree. We advise you to enquire further regarding the suitability of this program for your academic, professional requirements and job prospects before enr...