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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 time 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!(
"Time" => &[
NaiveTime::from_hms_milli_opt(2, 00, 3, 456).unwrap(),
NaiveTime::from_hms_milli_opt(2, 18, 3, 456).unwrap(),
NaiveTime::from_hms_milli_opt(2, 37, 3, 456).unwrap(),
NaiveTime::from_hms_milli_opt(2, 59, 3, 456).unwrap(),
],
)?;
// Create a new excel writer.
let mut excel_writer = PolarsExcelWriter::new();
// Set the time format.
excel_writer.set_dtype_format(DataType::Time, "hh:mm");
// Write the dataframe to Excel.
excel_writer.write_dataframe(&df)?;
// Save the file to disk.
excel_writer.save("dataframe.xlsx")?;
Ok(())
}