polars_excel_writer

The polars_excel_writer crate is a library for serializing Polars dataframes to Excel Xlsx files.

The crate uses rust_xlsxwriter to do the Excel serialization and is typically 5x faster than Polars when exporting large dataframes to Excel.

It provides a primary interface PolarsXlsxWriter which is a configurable Excel serializer that resembles the interface options provided by the Polars write_excel() dataframe method.

The crate also provides a secondary ExcelWriter interface which is a simpler Excel serializer that implements the Polars SerWriter trait to write a dataframe to an Excel Xlsx file. However, unless you have existing code that uses the SerWriter trait you should use the PolarsXlsxWriter interface.

Example

An example of writing a Polar Rust dataframe to an Excel file using the PolarsXlsxWriter interface.

use chrono::prelude::*;
use polars::prelude::*;

use polars_excel_writer::PolarsXlsxWriter;

fn main() -> PolarsResult<()> {
    // Create a sample dataframe for the example.
    let df: DataFrame = df!(
        "String" => &["North", "South", "East", "West"],
        "Integer" => &[1, 2, 3, 4],
        "Float" => &[4.0, 5.0, 6.0, 7.0],
        "Time" => &[
            NaiveTime::from_hms_milli_opt(2, 59, 3, 456).unwrap(),
            NaiveTime::from_hms_milli_opt(2, 59, 3, 456).unwrap(),
            NaiveTime::from_hms_milli_opt(2, 59, 3, 456).unwrap(),
            NaiveTime::from_hms_milli_opt(2, 59, 3, 456).unwrap(),
            ],
        "Date" => &[
            NaiveDate::from_ymd_opt(2022, 1, 1).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 2).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 3).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 4).unwrap(),
            ],
        "Datetime" => &[
            NaiveDate::from_ymd_opt(2022, 1, 1).unwrap().and_hms_opt(1, 0, 0).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 2).unwrap().and_hms_opt(2, 0, 0).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 3).unwrap().and_hms_opt(3, 0, 0).unwrap(),
            NaiveDate::from_ymd_opt(2022, 1, 4).unwrap().and_hms_opt(4, 0, 0).unwrap(),
        ],
    )?;

    // Create a new Excel writer.
    let mut xlsx_writer = PolarsXlsxWriter::new();

    // Write the dataframe to Excel.
    xlsx_writer.write_dataframe(&df)?;

    // Save the file to disk.
    xlsx_writer.save("dataframe.xlsx")?;

    Ok(())
}

Output file:

Performance

The table below shows the performance of writing a dataframe using Python Polars, Python Pandas and PolarsXlsxWriter.

See the Performance section of the docs for more detail.

See also

• The polars_excel_writer crate.
• The polars_excel_writer API docs at docs.rs.
• The polars_excel_writer repository.
• Roadmap of planned features.