YouTip

Python2 vs Python3

Python3 is the current version of Python. It is not backward-compatible with Python2, which is no longer maintained.

Key Differences

# Print is a function in Python3
print("Hello")         # Python3
# print "Hello"        # Python2 (syntax error in 3)

# Integer division
print(5 / 2)           # 2.5 in Python3 (was 2 in Python2)
print(5 // 2)          # 2 (floor division)

# Unicode strings
name = "Alice"         # Unicode by default in Python3

Modern Python3 Features

# f-strings (Python 3.6+)
name = "Alice"
print(f"Hello, {name}!")

# Walrus operator (Python 3.8+)
if (n := len("hello")) > 3:
    print(f"Length is {n}")

# Match statement (Python 3.10+)
match command:
    case "start":
        print("Starting")
    case "stop":
        print("Stopping")
    case _:
        print("Unknown")

Type Hints (Python 3.5+)

def greet(name: str) -> str:
    return f"Hello, {name}!"

age: int = 25
names: list = ["Alice", "Bob"]

Summary

• Python3 print() is a function, not a statement
• Division / returns float, use // for integer division
• f-strings provide easy string formatting
• match/case added in Python 3.10