Walrus Operator
The walrus operator (:=) in Python, introduced in Python 3.8, is also known as the assignment expression. It returns the value as well as assigning it. This can reduce many lines of code and greatly simplifies the language.
Example
# Without Walrus
numbers = [1,2,3]
numbers_length = len(numbers)
numbers_sum = sum(numbers)
numbers_description = {
"length": numbers_length
"sum": numbers_sum
}
# With Walrus - see how we save the variables and return the value
numbers = [1,2,3]
numbers_description = {
"length": numbers_length := len(numbers)
"sum": numbers_sum := sum(numbers)
}
Another Example
# Example code to read lines from a file and process non-empty lines
with open('example.txt', 'r') as file:
while (line := file.readline().strip()):
print(f"Processing line: {line}")
