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// SPDX-License-Identifier: MIT OR Apache-2.0
//
// Copyright 2022-2025, John McNamara, jmcnamara@cpan.org
//! An example of writing a Polar Rust dataframe to an Excel file. This example
//! demonstrates how to change the default format for Polars date types.
use chrono::prelude::*;
use polars::prelude::*;
use polars_excel_writer::PolarsExcelWriter;
fn main() -> PolarsResult<()> {
// Create a sample dataframe for the example.
let df: DataFrame = df!(
"Date" => &[
NaiveDate::from_ymd_opt(2023, 1, 11),
NaiveDate::from_ymd_opt(2023, 1, 12),
NaiveDate::from_ymd_opt(2023, 1, 13),
NaiveDate::from_ymd_opt(2023, 1, 14),
],
)?;
// Create a new Excel writer.
let mut excel_writer = PolarsExcelWriter::new();
// Set the date format.
excel_writer.set_dtype_format(DataType::Date, "mmm d yyyy");
// Write the dataframe to Excel.
excel_writer.write_dataframe(&df)?;
// Save the file to disk.
excel_writer.save("dataframe.xlsx")?;
Ok(())
}