app.py

import pandas as pd

from shiny import App, Inputs, Outputs, Session, reactive, render, ui
from shiny.types import FileInfo

app_ui = ui.page_fluid(
    ui.input_file("file1", "Choose CSV File", accept=[".csv"], multiple=False),
    ui.input_checkbox_group(
        "stats",
        "Summary Stats",
        choices=["Row Count", "Column Count", "Column Names"],
        selected=["Row Count", "Column Count", "Column Names"],
    ),
    ui.output_table("summary"),
)


def server(input: Inputs, output: Outputs, session: Session):
    @reactive.Calc
    def parsed_file():
        file: list[FileInfo] | None = input.file1()
        if file is None:
            return pd.DataFrame()
        return pd.read_csv(  # pyright: ignore[reportUnknownMemberType]
            file[0]["datapath"]
        )

    @output
    @render.table
    def summary():
        df = parsed_file()

        if df.empty:
            return pd.DataFrame()

        # Get the row count, column count, and column names of the DataFrame
        row_count = df.shape[0]
        column_count = df.shape[1]
        names = df.columns.tolist()
        column_names = ", ".join(str(name) for name in names)

        # Create a new DataFrame to display the information
        info_df = pd.DataFrame(
            {
                "Row Count": [row_count],
                "Column Count": [column_count],
                "Column Names": [column_names],
            }
        )

        # input.stats() is a list of strings; subset the columns based on the selected
        # checkboxes
        return info_df.loc[:, input.stats()]


app = App(app_ui, server)