Struct StringDictionary 

pub struct StringDictionary { /* private fields */ }

A dictionary-encoded string column.

Each row holds a u32 code into a table of unique values. The value table is stored Arrow-style as one UTF-8 byte buffer plus n_values() + 1 offsets, so both halves cross an FFI or wasm-bindgen boundary as plain numeric buffers (Uint32Array codes, Uint8Array bytes, Uint32Array offsets) and the consumer decodes each unique value once.

Codes are assigned in first-occurrence order, so encoding the same input always yields the same codes.

Implementations

impl StringDictionary

pub fn encode<'s>( values: impl IntoIterator<Item = &'s str>, ) -> Result<Self, BoundaryError>

Encode a sequence of strings.

Fails with CapacityExceeded if the row count or total value bytes do not fit in u32.

pub fn codes(&self) -> &[u32]

Per-row codes into the value table.

pub fn value_bytes(&self) -> &[u8]

Concatenated UTF-8 bytes of all unique values.

pub fn value_offsets(&self) -> &[u32]

Offsets into Self::value_bytes; value c spans value_offsets[c]..value_offsets[c + 1].

pub fn len(&self) -> usize

Number of rows.

pub fn is_empty(&self) -> bool

Returns true if there are no rows.

pub fn n_values(&self) -> usize

Number of unique values.

pub fn value(&self, code: u32) -> Option<&str>

The unique value for code, or None if the code is out of range.

pub fn get(&self, row: usize) -> Option<&str>

The decoded value of row row, or None if the row is out of range.

pub fn values(&self) -> impl Iterator<Item = &str> + '_

Iterate over the unique values in code order.

Trait Implementations

impl Clone for StringDictionary

fn clone(&self) -> StringDictionary

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StringDictionary

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

Formats the value using the given formatter.

impl Eq for StringDictionary

impl PartialEq for StringDictionary

fn eq(&self, other: &StringDictionary) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for StringDictionary