Cheat Sheet: Python Programming Fundamentals

 

Python Programming Fundamentals Cheat Sheet

Package/Method	Description	Syntax and Code Example
AND	Returns `True` if both statement1 and statement2 are `True`. Otherwise, returns `False`.	Syntax: 1 statement1 and statement2 Example: 1 2 3 4 5 6 7 8 9 marks = 90 attendance_percentage = 87 if marks >= 80 and attendance_percentage >= 85: print("qualify for honors") else: print("Not qualified for honors") # Output = qualify for honors
Class Definition	Defines a blueprint for creating objects and defining their attributes and behaviors.	Syntax: 1 class ClassName: # Class attributes and methods Example: 1 2 3 4 class Person: def __init__(self, name, age): self.name = name self.age = age
Define Function	A `function` is a reusable block of code that performs a specific task or set of tasks when called.	Syntax: 1 def function_name(parameters): # Function body Example: 1 def greet(name): print("Hello,", name)
Equal(==)	Checks if two values are equal.	Syntax: 1 variable1 == variable2 Example 1: 1 5 == 5 returns True Example 2: 1 age = 25 age == 30 returns False
For Loop	A `for` loop repeatedly executes a block of code for a specified number of iterations or over a sequence of elements (list, range, string, etc.).	Syntax: 1 for variable in sequence: # Code to repeat Example 1: 1 2 for num in range(1, 10): print(num) Example 2: 1 2 3 fruits = ["apple", "banana", "orange", "grape", "kiwi"] for fruit in fruits: print(fruit)
Function Call	A function call is the act of executing the code within the function using the provided arguments.	Syntax: 1 function_name(arguments) Example: 1 greet("Alice")
Greater Than or Equal To(>=)	Checks if the value of variable1 is greater than or equal to variable2.	Syntax: 1 variable1 >= variable2 Example 1: 1 5 >= 5 and 9 >= 5 returns True Example 2: 1 2 3 quantity = 105 minimum = 100 quantity >= minimum returns True
Greater Than(>)	Checks if the value of variable1 is greater than variable2.	Syntax: 1 variable1 > variable2 Example 1: 9 > 6 returns True Example 2: 1 2 3 age = 20 max_age = 25 age > max_age returns False
If Statement	Executes code block `if` the condition is `True`.	Syntax: 1 if condition: #code block for if statement Example: 1 2 if temperature > 30: print("It's a hot day!")
If-Elif-Else	Executes the first code block if condition1 is `True`, otherwise checks condition2, and so on. If no condition is `True`, the else block is executed.	Syntax: 1 2 3 4 5 6 7 8 if condition1: # Code if condition1 is True elif condition2: # Code if condition2 is True else: # Code if no condition is True Example: 1 2 3 4 5 6 7 8 9 score = 85 # Example score if score >= 90: print("You got an A!") elif score >= 80: print("You got a B.") else: print("You need to work harder.") # Output = You got a B.
If-Else Statement	Executes the first code block if the condition is `True`, otherwise the second block.	Syntax: 1 2 if condition: # Code, if condition is True else: # Code, if condition is False Example: 1 2 3 4 if age >= 18: print("You're an adult.") else: print("You're not an adult yet.")
Less Than or Equal To(<=)	Checks if the value of variable1 is less than or equal to variable2.	Syntax: 1 variable1 <= variable2 Example 1: 1 5 <= 5 and 3 <= 5 returns True Example 2: 1 2 3 size = 38 max_size = 40 size <= max_size returns True
Less Than(<)	Checks if the value of variable1 is less than variable2.	Syntax: 1 variable1 < variable2 Example 1: 1 4 < 6 returns True Example 2: 1 2 3 score = 60 passing_score = 65 score < passing_score returns True
Loop Controls	`break` exits the loop prematurely. `continue` skips the rest of the current iteration and moves to the next iteration.	Syntax: 1 2 3 4 5 6 7 for: # Code to repeat if # boolean statement break for: # Code to repeat if # boolean statement continue Example 1: 1 2 3 4 for num in range(1, 6): if num == 3: break print(num) Example 2: 1 2 3 4 for num in range(1, 6): if num == 3: continue print(num)
NOT	Returns `True` if variable is `False`, and vice versa.	Syntax: 1 !variable Example: 1 !isLocked returns True if the variable is False (i.e., unlocked).
Not Equal(!=)	Checks if two values are not equal.	Syntax: 1 variable1 != variable2 Example: 1 2 3 a = 10 b = 20 a != b returns True Example 2: 1 2 count=0 count != 0 returns False
Object Creation	Creates an instance of a class (object) using the class constructor.	Syntax: 1 object_name = ClassName(arguments) Example: 1 person1 = Person("Alice", 25)
OR	Returns `True` if either statement1 or statement2 (or both) are `True`. Otherwise, returns `False`.	Syntax: 1 statement1 || statement2 Example: 1 2 "Farewell Party Invitation" Grade = 12 grade == 11 or grade == 12 returns True
range()	Generates a sequence of numbers within a specified range.	Syntax: 1 2 3 range(stop) range(start, stop) range(start, stop, step) Example: 1 2 3 range(5) #generates a sequence of integers from 0 to 4. range(2, 10) #generates a sequence of integers from 2 to 9. range(1, 11, 2) #generates odd integers from 1 to 9.
Return Statement	`Return` is a keyword used to send a value back from a function to its caller.	Syntax: 1 return value Example: 1 2 def add(a, b): return a + b result = add(3, 5)
Try-Except Block	Tries to execute the code in the try block. If an exception of the specified type occurs, the code in the except block is executed.	Syntax: 1 2 try: # Code that might raise an exception except ExceptionType: # Code to handle the exception Example: 1 2 3 4 try: num = int(input("Enter a number: ")) except ValueError: print("Invalid input. Please enter a valid number.")
Try-Except with Else Block	Code in the `else` block is executed if no exception occurs in the try block.	Syntax: 1 2 3 try: # Code that might raise an exception except ExceptionType: # Code to handle the exception else: # Code to execute if no exception occurs Example: 1 2 3 4 5 6 try: num = int(input("Enter a number: ")) except ValueError: print("Invalid input. Please enter a valid number") else: print("You entered:", num)
Try-Except with Finally Block	Code in the `finally` block always executes, regardless of whether an exception occurred.	Syntax: 1 2 3 try: # Code that might raise an exception except ExceptionType: # Code to handle the exception finally: # Code that always executes Example: 1 2 3 4 5 6 7 try: file = open("data.txt", "r") data = file.read() except FileNotFoundError: print("File not found.") finally: file.close()
While Loop	A `while` loop repeatedly executes a block of code as long as a specified condition remains `True`.	Syntax: 1 while condition: # Code to repeat Example: 1 2 count = 0 while count < 5: print(count) count += 1