Keywords Related to Flow Control

  • if, elif, else: Used for conditional branching, controlling which blocks of code execute based on conditions.
  • for: Used for iterating over a sequence of items (like lists, tuples, strings, ranges).
  • while: Used for creating loops that continue as long as a condition is true.
  • break: Exits a loop prematurely.
  • continue: Skips to the next iteration of a loop.
  • pass: Placeholder statement that does nothing; often used during development when syntax requires a statement, but you haven’t written the code yet.
 1# Flow Control
 2count = 0
 3while count < 5:
 4    print(f"Count: {count}")
 5    count += 1
 6
 7for i in range(3):
 8    print(f"Iteration: {i}")
 9
10if count == 5:
11    print("Count reached 5!")
12else:
13    print("Count is not 5.")

Keywords Related to Functions and Scope

  • def: Defines a function, a reusable block of code.
  • return: Sends a value back from a function.
  • lambda: Creates a small, anonymous function.
  • global: Accesses a global variable from within a function’s scope.
  • nonlocal: Modifies a variable in an enclosing function’s scope (not the global scope).
1# Functions
2def greet(name):
3    return f"Hello, {name}!"
4
5message = greet("Alice")
6print(message)
7#Output: Hello, Alice

Keywords Related to Classes and Objects

  • class: Defines a class, a blueprint for creating objects (instances).
  • self: A reference to the current instance of the class.
  • init: The constructor method, called when an object is created.
  • super: Provides access to methods and attributes of a parent class.
 1# Classes
 2class Dog:
 3    def __init__(self, name, breed):
 4        self.name = name
 5        self.breed = breed
 6
 7    def bark(self):
 8        return "Woof!"
 9
10my_dog = Dog("Jack", "GoldenDoodle")
11print(f"{my_dog.name} says {my_dog.bark()}")
12# Jack says Woof!

Keywords Related to Error Handling

  • try: A block of code where you anticipate potential errors.
  • except: Handles a specific type of exception (error).
  • finally: A block of code that always executes, whether an exception occurred or not.
  • raise: Manually triggers an exception.
1# Error Handling
2try:
3    result = 10 / 0 
4except ZeroDivisionError:
5    print("You cannot divide by zero!")

Keywords Related to Boolean Logic and Comparisons

  • True, False: The two Boolean values, representing truthiness or falseness.
  • and, or, not: Logical operators used to combine or modify Boolean expressions.
  • is, is not: Identity operators, checking if two variables refer to the same object in memory.
  • in, not in: Membership operators, checking if a value is present in a sequence.
 1temperature = 25
 2is_sunny = True
 3wind_speed = 15
 4
 5# Comparisons
 6is_warm = temperature > 20  # True
 7is_windy = wind_speed > 10  # True
 8
 9# Boolean Logic
10good_weather = is_warm and is_sunny  # True (both conditions are True)
11stay_inside = not is_sunny or is_windy  # True (at least one condition is True)

Keywords with Special Meanings

  • None: Represents the absence of a value.
  • as: Used for aliasing (giving a different name to an imported module or exception).
  • with: Simplifies working with resources that need to be opened and closed properly (e.g., files).
  • yield: Used in generator functions, which produce a sequence of values one at a time.
  • del: Deletes objects, variables, or slices from a list.
  • assert: Checks if a condition is true; if not, it raises an exception.
1# Other Keywords
2my_list = [1, 2, 3]
3del my_list[0] 
4print(my_list)  
5
6x = 5
7assert x > 0, "x should be a positive number"

Notes:

  • Case-Sensitivity: Python keywords are case-sensitive (e.g., for is different from For).
  • Reserved: You cannot use keywords as variable, function, or class names.

Read: Python Built-In Classes