Update row style from DataTable when pressing a given key

[msempere]

Hi!
I've been reading the documentation and there's something I don't fully understand how put the pieces together to achieve it. Let's say I have a DataTable that gets populated from a CSV file and I'd like when pressing the a key to change the style of that row, set all values from all cells to red color, like and add operation, so then, evaluate all those added rows and perform an operation with them.
Is the only way using update_cell on each individual column value or is there a more optimal way?

[TomJGooding]

I'd like when pressing the a key to change the style of that row, set all values from all cells to red color [...]

This recent discussion might be helpful. You can apply styles programmatically with rich renderables, but not with CSS as this works at the widget level.

Here's a quick example, though there might be a more efficient way:

from textual.app import App, ComposeResult
from textual.coordinate import Coordinate
from textual.widgets import DataTable, Footer

ROWS = [
    ("lane", "swimmer", "country", "time"),
    (4, "Joseph Schooling", "Singapore", 50.39),
    (2, "Michael Phelps", "United States", 51.14),
    (5, "Chad le Clos", "South Africa", 51.14),
    (6, "László Cseh", "Hungary", 51.14),
    (3, "Li Zhuhao", "China", 51.26),
    (8, "Mehdy Metella", "France", 51.58),
    (7, "Tom Shields", "United States", 51.73),
    (1, "Aleksandr Sadovnikov", "Russia", 51.84),
    (10, "Darren Burns", "Scotland", 51.84),
]


class TableApp(App):
    BINDINGS = [
        ("a", "style_highlighted_row", "Apply styling to highlighted row"),
    ]

    def compose(self) -> ComposeResult:
        yield DataTable()
        yield Footer()


    def on_mount(self) -> None:
        table = self.query_one(DataTable)
        rows = iter(ROWS)
        table.add_columns(*next(rows))
        table.add_rows(rows)

    def action_style_highlighted_row(self) -> None:
        table = self.query_one(DataTable)
        row_idx: int = table.cursor_row
        row_cells = table.get_row_at(row_idx)
        for col_idx, cell_value in enumerate(row_cells):
            cell_coordinate = Coordinate(row_idx, col_idx)
            table.update_cell_at(
                cell_coordinate,
                f"[red]{cell_value}[/red]",
            )


app = TableApp()
if __name__ == "__main__":
    app.run()

[...] like and add operation, so then, evaluate all those added rows and perform an operation with them.

Sorry but I'm not sure I understand what you mean here - could you provide an example?

[EDIT: Forgot to add the footer!]

[TomJGooding]

Right, because get_row just returns a list of values. You haven't actually updated anything in the DataTable.

[pawamoy]

Yep. Hence the call to refresh(). But without incrementing the internal counter, it doesn't actually refresh.

[TomJGooding]

Sorry I'm actually now more confused. Could you provide a MRE showing how you're using your Checkbox class in a DataTable?

[pawamoy]

Sure!

from textual.app import App
from textual.widgets import DataTable, Static, Input


class Checkbox:
    def __init__(self):
        self.checked = False

    def __rich__(self):
        return "[green]■[/]" if self.checked else ""

    def toggle(self):
        self.checked = not self.checked
        return self.checked


class MyApp(App):
    BINDINGS = [
        ("t", "toggle", "Toggle"),
        ("T", "force_toggle", "Toggle"),
    ]

    def compose(self):
        yield Static(
            "Hit lower t to toggle checkbox, then move focus with tab to refresh.\n"
            "Hit upper T to force toggle checkbox, no need to move focus."
        )
        yield DataTable()
        yield Input()

    def on_mount(self):
        table = self.query_one(DataTable)
        table.cursor_type = "row"
        for column in ("?", "One", "Two"):
            table.add_column(column)
        rows = [
            ("Mario", "Luigi"),
            ("Wario", "Waluigi"),
        ]
        table.add_rows((Checkbox(), *row) for row in rows)

    def action_toggle(self):
        table = self.query_one(DataTable)
        key = table.coordinate_to_cell_key(table.cursor_coordinate).row_key
        table.get_row(key)[0].toggle()
        table.refresh()

    def action_force_toggle(self):
        table = self.query_one(DataTable)
        key = table.coordinate_to_cell_key(table.cursor_coordinate).row_key
        table.get_row(key)[0].toggle()
        table._update_count += 1
        table.refresh()


if __name__ == "__main__":
    app = MyApp()
    app.run()

[chbndrhnns]

    table._update_count += 1

Modifying an internal counter seems kind of ugly. Is there another approach here? I am also thinking about a feature request but I do not know how to generalize the request a bit