What does colon equal (:=) in Python mean?

Question

What does the := operand mean, more specifically for Python?

Can someone explain how to read this snippet of code?

node := root, cost =          


        

Answer 1

Happy 3.8 Release on 14th of October!

There is new syntax := that assigns values to variables as part of a larger expression. It is affectionately known as “the walrus operator” due to its resemblance to the eyes and tusks of a walrus.

In this example, the assignment expression helps avoid calling len() twice:

if (n := len(a)) > 10:
    print(f"List is too long ({n} elements, expected <= 10)")

What’s New In Python 3.8 - Assignment expressions