Py Walrus Operator — Free Python Tutorial
Learn Py Walrus Operator in Python with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
TL;DR: Learn Py Walrus Operator in Python with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Py Walrus Operator in Python
The walrus operator (:=), introduced in Python 3.8, is the "assignment expression" operator. It assigns a value to a variable AND returns that value — all inside an expression. The name comes from the := shape resembling a walrus face.
Its biggest use is eliminating redundant calls. Without it you might call an expensive function twice: once to check a condition and once to use the result. With :=, you assign and check in one step.
Classic patterns: while loops that read data until exhausted, list comprehensions that filter and reuse a computed value, and if-elif chains that avoid repeated function calls.
Walrus operator has lower precedence than most operators, so you usually need parentheses when using it inside an expression: while (line := f.readline()): ...
Py Walrus Operator — Syntax
# Without walrus operator
data = compute()
if data:
use(data)
# With walrus operator — one line!
if data := compute():
use(data)
# In while loop
while chunk := file.read(1024):
process(chunk)
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