Struct RowsBatchRef

pub struct RowsBatchRef<'a, T> { /* private fields */ }

This struct is similar to RowsBatch, but it holds a reference to a slice of rows (instead of an owned vector) and an offset in each row.

It is guaranteed that all rows in self.rows have a length of at least row_len + offset. The effective row returned by row method is &self.rows[index][self.offset..self.offset + self.row_len]. Unfortunately, due to lifetime issues, we can’t unify RowsBatch and RowsBatchRef into a single generic struct parameterized by the container type.

Implementations

impl<'a, T> RowsBatchRef<'a, T>

pub fn new(rows: &'a [&'a [T]], row_len: usize) -> Self

Create a new RowsBatchRef from a slice of rows and the given row length.

Panics

In case if any of the rows has a length smaller than row_len.

pub fn new_with_offset( rows: &'a [&'a [T]], offset: usize, row_len: usize, ) -> Self

Create a new RowsBatchRef from a slice of rows and the given row length and offset.

Panics

In case if any of the rows has a length smaller than from offset + row_len.

pub unsafe fn new_unchecked(rows: &'a [&'a [T]], row_len: usize) -> Self

Create a new RowsBatchRef from a slice of rows and the given row length and offset.

Safety

This function is unsafe because it does not check if the rows have the enough length. It is the caller’s responsibility to ensure that row_len is less than or equal to the length of each row.

pub unsafe fn new_with_offset_unchecked( rows: &'a [&'a [T]], offset: usize, row_len: usize, ) -> Self

Create a new RowsBatchRef from a slice of rows and the given row length and offset.

Safety

This function is unsafe because it does not check if the rows have the enough length. It is the caller’s responsibility to ensure that offset + row_len is less than or equal to the length of each row.

pub fn iter(&self) -> impl Iterator<Item = &'a [T]> + '_

pub fn row(&self, index: usize) -> &'a [T]

pub fn n_rows(&self) -> usize

pub fn row_len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn map(&self, indices: impl AsRef<[usize]>) -> RowsBatch<'a, T>

Returns a new RowsBatch with the specified rows selected by the given indices.

pub fn columns_subrange(&self, range: impl RangeBounds<usize>) -> Self

Returns a new RowsBatchRef with the specified columns selected by the given indices range.