textual/questions/pass-args-to-app.question.md

title, alt_titles

title	alt_titles
How do I pass arguments to an app?	pass arguments to an application pass parameters to an app pass parameters to an application

When creating your App class, override __init__ as you would when inheriting normally. For example:

from textual.app import App, ComposeResult
from textual.widgets import Static

class Greetings(App[None]):

    def __init__(self, greeting: str="Hello", to_greet: str="World") -> None:
        self.greeting = greeting
        self.to_greet = to_greet
        super().__init__()

    def compose(self) -> ComposeResult:
        yield Static(f"{self.greeting}, {self.to_greet}")

Then the app can be run, passing in various arguments; for example:

# Running with default arguments.
Greetings().run()

# Running with a keyword arguyment.
Greetings(to_greet="davep").run()

# Running with both positional arguments.
Greetings("Well hello", "there").run()