> If it's okay to end up with the second one of your examples (without the ":=" operator), why did we need to add the walrus operator at all?
A couple of reasons:
- The walrus eliminates a line of code in the very common scenario where you would prefer not to recalculate (or retype) y().
- The walrus makes it easy to avoid recalculating y() in the less common scenario where you need to avoid doing that.
> I don't find this to be a clear statement at all.
Nonetheless, it is the normal English syntax used to name something and then immediately define the meaning of that name. If you want to map the Python structure to an equivalent English structure, that is the equivalent English structure. ("Thomas Jefferson, the third president, was a man about whom much can be said.") If you want to map the Python code to an English statement of what the code does, use the reading I first suggested, "if y(), do something with it". If you want to dictate Python code to an English speaker, use the reading "if x colon-equals y()".
So let me ask you: is the problem you'd like to solve "I want to understand what this code does", is it "I like thinking about English grammar", or is it "I'm too busy to type my own code; that's what my secretary is for"?