Multiple conditions for "walrus operator" assignment

Question

I'd like to know if it's possible to use the "walrus operator" to assign the value based on some condition as well as existing. For example, assign the string to post_url if that string contains some substring:

if post_url := data.get("Post url") and ("youtube" in data.get("Post url")):
    # Do something with post_url
else:
    # Do something else

However, this is just assigning the boolean value to post_url due to the evaluation of the and operation.

Use parentheses for the grouping you want - `post_url := (...)`. Alternatively `"youtube" in data.get("Post url", [])` would factor out the `and`. — jonrsharpe, Apr 27 '20 at 13:57
@jonrsharpe thanks for the comment. I tried if post_url := "youtube" in data.get("Post url", []) which still returns the boolean as does if post_url := (data.get("Post url") and "youtube" in data.get("Post url")): — Shaun Barney, Apr 27 '20 at 14:17
Oh, so you want `if (post_url := data.get("Post url")) and "youtube" in post_url:`? You don't need to double up the `.get` — jonrsharpe, Apr 27 '20 at 14:20

score 3 · Accepted Answer · answered Apr 27 '20 at 14:21

You can use parentheses to group this how you want, you don't even need to repeat the data.get:

if (post_url := data.get("Post url")) and "youtube" in post_url:
    # Do something with post_url
else:
    # Do something else

This will assign a value to post_url either way, so you can access None or the URL not containing "youtube" in the else block.

Multiple conditions for "walrus operator" assignment

1 Answers1