Function polars_core::utils::accumulate_dataframes_vertical

source · 
pub fn accumulate_dataframes_vertical<I>(dfs: I) -> PolarsResult<DataFrame>where
    I: IntoIterator<Item = DataFrame>,
Expand description

This takes ownership of the DataFrame so that drop is called earlier.

Examples found in repository?
src/frame/groupby/mod.rs (line 886)
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    pub fn par_apply<F>(&self, f: F) -> PolarsResult<DataFrame>
    where
        F: Fn(DataFrame) -> PolarsResult<DataFrame> + Send + Sync,
    {
        let df = self.prepare_apply()?;
        let dfs = self
            .get_groups()
            .par_iter()
            .map(|g| {
                // safety
                // groups are in bounds
                let sub_df = unsafe { take_df(&df, g) };
                f(sub_df)
            })
            .collect::<PolarsResult<Vec<_>>>()?;

        let mut df = accumulate_dataframes_vertical(dfs)?;
        df.as_single_chunk();
        Ok(df)
    }

    /// Apply a closure over the groups as a new DataFrame.
    pub fn apply<F>(&self, mut f: F) -> PolarsResult<DataFrame>
    where
        F: FnMut(DataFrame) -> PolarsResult<DataFrame> + Send + Sync,
    {
        let df = self.prepare_apply()?;
        let dfs = self
            .get_groups()
            .iter()
            .map(|g| {
                // safety
                // groups are in bounds
                let sub_df = unsafe { take_df(&df, g) };
                f(sub_df)
            })
            .collect::<PolarsResult<Vec<_>>>()?;

        let mut df = accumulate_dataframes_vertical(dfs)?;
        df.as_single_chunk();
        Ok(df)
    }