Remove All Child Widgets

[aaronst]

I have a container in which I want to set completely different widgets reactively. I've been doing:

def watch_blah(self, new_value: str) -> None:
    for child in self.children:
        child.remove()

    # self.mount(*widgets) based on new_value

This works, but I've noticed that it can be a bit slow to remove for more than five or so children. I'm guessing this is because it redraws for every child? Is there a better way to do this? Having a remove_all() or remove_children() method to remove all or maybe a subset of child widgets in one go would be handy I think.

[davep]

One way to do this would be to use the child combinator to get a query of all the children of a particular node, then use the remove loop-free operation with that query.

However... internally it does more or less what you're doing right now and has the same performance hit. I don't think it's been raised as a particular issue just yet, but @willmcgugan has identified that remove on a query needs some work to make it faster (this came about last weekend when I ran into the same thing as you, only using what I'm suggesting here, to remove 1,600 widgets in one go).

In short: personally I think remove on a query is the way to go and the speed should then improve in a future release of Textual.

[aaronst]

Ah yes, I did see the tweets on that. 😆 Thanks for the answer, I'll use query() as you suggest.

[davep]

Just to update: #1147 should be incoming with the next release.

[aaronst]

Awesome!