Python Syntax

Python is a high-level, interpreted programming language known for its simplicity and readability. This chapter provides an overview of the basic syntax of Python, including examples to illustrate each concept.

1. Comments

Comments in Python start with the hash character (#) and extend to the end of the line. Comments are ignored by the Python interpreter and are used to add notes or explanations in the code.

# This is a comment
print("Hello, World!")  # This is another comment

2. Variables

Variables in Python are used to store data values. A variable is created the moment you first assign a value to it.

x = 5
y = "Hello"
print(x)
print(y)

3. Data Types

Python has several built-in data types, including integers, floats, strings, lists, tuples, dictionaries, and more.

x = 5              # int
y = 5.5            # float
z = "Hello"       # string
a = [1, 2, 3]     # list
b = (1, 2, 3)     # tuple
c = {"name": "Alice", "age": 25}  # dictionary

4. Print Function

The print() function is used to output data to the console.

print("Hello, World!")
print(x)
print(y + " World!")

5. Indentation

Indentation is very important in Python. It is used to define the level of code blocks, such as functions, loops, and conditional statements. Python uses whitespace (spaces or tabs) for indentation, not braces.

if x > 0:
    print("x is positive")
else:
    print("x is not positive")

6. Conditional Statements

Conditional statements are used to perform different actions based on different conditions. The most common conditional statements in Python are if, elif, and else.

x = 10

if x > 0:
    print("x is positive")
elif x == 0:
    print("x is zero")
else:
    print("x is negative")

7. Loops

Loops are used to execute a block of code repeatedly. Python provides two types of loops: for loops and while loops.

7.1 For Loop

for i in range(5):
    print(i)

7.2 While Loop

i = 0
while i < 5:
    print(i)
    i += 1

8. Functions

Functions are defined using the def keyword. They are used to encapsulate code that performs a specific task.

def greet(name):
    print("Hello, " + name)

greet("Alice")
greet("Bob")

9. Classes and Objects

Python is an object-oriented programming language. You can define your own classes and create objects from those classes.

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def greet(self):
        print("Hello, my name is " + self.name)

p1 = Person("Alice", 25)
p1.greet()

p2 = Person("Bob", 30)
p2.greet()

Conclusion

This chapter provided an overview of the basic syntax of Python, covering comments, variables, data types, the print function, indentation, conditional statements, loops, functions, and classes and objects. Understanding these basic concepts is essential for writing Python programs.