Struct TidyView 

pub struct TidyView { /* private fields */ }

Zero-copy virtual view over a shared DataFrame.

The base data is behind an Rc and never modified. Filters create bitmasks, selects narrow projections, sorts store permutation vectors. Data is only copied when you explicitly materialize or mutate.

Implementations

impl TidyView

pub fn new(df: DataFrame) -> Self

Create a new TidyView over the entire DataFrame.

pub fn from_rc(base: Rc<DataFrame>) -> Self

Create from a shared Rc.

pub fn nrows(&self) -> usize

Number of visible rows.

pub fn ncols(&self) -> usize

Number of visible columns.

pub fn mask(&self) -> &BitMask

Get the bitmask (for auditing).

pub fn base(&self) -> &DataFrame

Get the base DataFrame (for auditing).

pub fn filter(&self, predicate: &DExpr) -> Result<TidyView, TidyError>

Filter rows by predicate. Returns a new TidyView with an updated bitmask. No data is copied — just bits are flipped.

pub fn select(&self, cols: &[&str]) -> Result<TidyView, TidyError>

Select specific columns by name. Returns a new TidyView with a narrowed projection. No data is copied.

pub fn mutate( &self, assignments: &[(&str, DExpr)], ) -> Result<DataFrame, TidyError>

Add or replace columns. Materializes the view and returns a new DataFrame.

Uses snapshot semantics: all column references resolve against the column list frozen before any assignments execute.

pub fn group_by(&self, keys: &[&str]) -> Result<GroupedTidyView, TidyError>

Group rows by one or more key columns.

Groups appear in first-occurrence order (deterministic, not hash-dependent).

pub fn arrange(&self, keys: &[ArrangeKey]) -> Result<TidyView, TidyError>

Sort visible rows by one or more keys. Stores the result as a lazy permutation vector — no data is materialized.

pub fn slice_head(&self, n: usize) -> TidyView

Take the first N visible rows.

pub fn slice_tail(&self, n: usize) -> TidyView

Take the last N visible rows.

pub fn slice_sample(&self, n: usize, seed: u64) -> TidyView

Deterministic random sample of N rows. Same seed = same rows, always.

pub fn distinct(&self, cols: &[&str]) -> Result<TidyView, TidyError>

Keep only unique rows by the given column subset.

pub fn inner_join( &self, right: &TidyView, on: &[(&str, &str)], ) -> Result<DataFrame, TidyError>

Inner join: rows where keys match in both tables.

pub fn left_join( &self, right: &TidyView, on: &[(&str, &str)], ) -> Result<DataFrame, TidyError>

Left join: all left rows, matched right rows or defaults.

pub fn materialize(&self) -> Result<DataFrame, TidyError>

Materialize the view into a new DataFrame (mask + projection applied).

pub fn column_names(&self) -> Vec<String>

Column names visible through the current projection.

Trait Implementations

impl Clone for TidyView

fn clone(&self) -> TidyView

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TidyView

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.