What is the walrus operator (:=) in Python 3.8+?

Question

Accepted Answer

**Walrus operator** — assigns value to a variable as part of an expression.

```python
# Without walrus operator
line = input("Enter: ")
while line != "quit":
    process(line)
    line = input("Enter: ")

# With walrus operator
while (line := input("Enter: ")) != "quit":
    process(line)

# In list comprehension
import re
text = "Call 555-1234 or 555-5678"
numbers = [match.group() for match in (m := re.finditer(r"\d{3}-\d{4}", text))]

# In if conditions
if (n := len(data)) > 10:
    print(f"Too long: {n} items")
```

**Benefits:**
- Eliminates redundant variable assignment.
- Cleaner loop and comprehension patterns.
- Avoids recomputation in comprehensions.

Python: What is the walrus operator (:=) in Python 3.8+?