Constants and Walrus Operator

Constants and the Walrus Operator

Python has no built-in constant type — by convention, use ALL_CAPS.

MAX_SIZE = 1000
PI = 3.14159
DB_URL = "localhost"

Introduced in Python 3.8, assigns and returns a value in one expression.

# Without walrus
data = get_data()
if data:
    process(data)

# With walrus
if data := get_data():
    process(data)

while chunk := file.read(8192):
    process(chunk)

Pro Tip

The walrus operator reduces repetition in while loops and comprehensions.