Struct polars_io::parquet::BatchedWriter

pub struct BatchedWriter<W: Write> { /* private fields */ }

Available on crate feature feature only.

Implementations

impl<W: Write> BatchedWriter<W>

pub fn write_batch(&mut self, df: &DataFrame) -> PolarsResult<()>

Write a batch to the parquet writer.

Panics

The caller must ensure the chunks in the given DataFrame are aligned.

Examples found in repository

src/parquet/write.rs (line 185)

    pub fn finish(self, df: &mut DataFrame) -> PolarsResult<u64> {
        // ensures all chunks are aligned.
        df.rechunk();

        if let Some(n) = self.row_group_size {
            let n_splits = df.height() / n;
            if n_splits > 0 {
                *df = accumulate_dataframes_vertical_unchecked(split_df(df, n_splits)?);
            }
        };
        let mut batched = self.batched(&df.schema())?;
        batched.write_batch(df)?;
        batched.finish()
    }

pub fn finish(&mut self) -> PolarsResult<u64>

Writes the footer of the parquet file. Returns the total size of the file.

Examples found in repository

src/parquet/write.rs (line 186)

    pub fn finish(self, df: &mut DataFrame) -> PolarsResult<u64> {
        // ensures all chunks are aligned.
        df.rechunk();

        if let Some(n) = self.row_group_size {
            let n_splits = df.height() / n;
            if n_splits > 0 {
                *df = accumulate_dataframes_vertical_unchecked(split_df(df, n_splits)?);
            }
        };
        let mut batched = self.batched(&df.schema())?;
        batched.write_batch(df)?;
        batched.finish()
    }