Python Syntax

Python Syntax

1. Python File & Execution

• Python files use the .py extension.

• Run a file:

  python file_name.py
  

• Indentation is required in Python — no {} for code blocks.

---

2. Indentation

• Use spaces (recommended: 4 spaces) or tabs — be consistent.

• Example:

  if True:
      print("Indented code runs")
  

---

3. Comments

• Single-line:

  # This is a comment
  

• Multi-line (technically multi-line strings used as comments):

  """
  This is a
  multi-line comment
  """
  

---

4. Variables

• No need to declare type — Python is dynamically typed.

• Example:

  name = "Alice"    # string
  age = 25          # integer
  height = 5.6      # float
  is_student = True # boolean
  

---

5. Data Types

• Basic: int, float, str, bool

• Collections:

  • List – ordered, changeable: fruits = ["apple", "banana"]
  • Tuple – ordered, unchangeable: point = (4, 5)
  • Set – unordered, unique: unique_nums = {1, 2, 3}
  • Dictionary – key-value: person = {"name": "Alice", "age": 25}

---

6. Printing Output

print("Hello, World!")
print("Name:", name)
print(f"Name: {name}, Age: {age}")

---

7. Taking Input

name = input("Enter your name: ")
print("Hello", name)

---

8. Conditional Statements

x = 10
if x > 5:
    print("Greater than 5")
elif x == 5:
    print("Equal to 5")
else:
    print("Less than 5")

---

9. Loops

• For loop:

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

• While loop:

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

---

10. Functions

def greet(name):
    return f"Hello, {name}"

print(greet("Alice"))

---

11. Importing Modules

import math
print(math.sqrt(16))

from datetime import date
print(date.today())