Struct FixedSizeBinaryDictionaryBuilder

pub struct FixedSizeBinaryDictionaryBuilder<K>
where
    K: ArrowDictionaryKeyType,
{
    state: RandomState,
    dedup: HashTable<usize>,
    keys_builder: PrimitiveBuilder<K>,
    values_builder: FixedSizeBinaryBuilder,
    byte_width: i32,
}

Builder for DictionaryArray of FixedSizeBinaryArray

The output array has a dictionary of unique, fixed-size binary values. The builder handles deduplication.

Example

// Build 3 byte FixedBinaryArrays
let byte_width = 3;
let mut builder = FixedSizeBinaryDictionaryBuilder::<Int8Type>::new(3);
builder.append("abc").unwrap();
builder.append_null();
builder.append(b"def").unwrap();
builder.append(b"def").unwrap(); // duplicate value
// Result is a Dictionary Array
let array = builder.finish();
let dict_array = array.as_any().downcast_ref::<DictionaryArray<Int8Type>>().unwrap();
// The array represents "abc", null, "def", "def"
assert_eq!(array.keys().len(), 4);
// but there are only 2 unique values
assert_eq!(array.values().len(), 2);
let values = dict_array.values().as_any().downcast_ref::<FixedSizeBinaryArray>().unwrap();
assert_eq!(values.value(0), "abc".as_bytes());
assert_eq!(values.value(1), "def".as_bytes());

Fields

state: RandomState

dedup: HashTable<usize>

keys_builder: PrimitiveBuilder<K>

values_builder: FixedSizeBinaryBuilder

byte_width: i32

Implementations

impl<K> FixedSizeBinaryDictionaryBuilder<K>

where K: ArrowDictionaryKeyType,

pub fn new(byte_width: i32) -> Self

Creates a new FixedSizeBinaryDictionaryBuilder

pub fn with_capacity( keys_capacity: usize, value_capacity: usize, byte_width: i32, ) -> Self

Creates a new FixedSizeBinaryDictionaryBuilder with the provided capacities

keys_capacity: the number of keys, i.e. length of array to build value_capacity: the number of distinct dictionary values, i.e. size of dictionary byte_width: the byte width for individual values in the values array

impl<K> FixedSizeBinaryDictionaryBuilder<K>

where K: ArrowDictionaryKeyType,

fn get_or_insert_key( &mut self, value: impl AsRef<[u8]>, ) -> Result<K::Native, ArrowError>

pub fn append( &mut self, value: impl AsRef<[u8]>, ) -> Result<K::Native, ArrowError>

Append a value to the array. Return an existing index if already present in the values array or a new index if the value is appended to the values array.

Returns an error if the new index would overflow the key type.

pub fn append_null(&mut self)

Appends a null slot into the builder

pub fn append_value(&mut self, value: impl AsRef<[u8]>)

Infallibly append a value to this builder

Panics

Panics if the resulting length of the dictionary values array would exceed T::Native::MAX

pub fn finish(&mut self) -> DictionaryArray<K>

Builds the DictionaryArray and reset this builder.

pub fn finish_cloned(&self) -> DictionaryArray<K>

Builds the DictionaryArray without resetting the builder.

Trait Implementations

impl<K> ArrayBuilder for FixedSizeBinaryDictionaryBuilder<K>

where K: ArrowDictionaryKeyType,

fn as_any(&self) -> &dyn Any

Returns the builder as an non-mutable Any reference.

fn as_any_mut(&mut self) -> &mut dyn Any

Returns the builder as an mutable Any reference.

fn into_box_any(self: Box<Self>) -> Box<dyn Any>

Returns the boxed builder as a box of Any.

fn len(&self) -> usize

Returns the number of array slots in the builder

fn finish(&mut self) -> ArrayRef

Builds the array and reset this builder.

fn finish_cloned(&self) -> ArrayRef

Builds the array without resetting the builder.

fn is_empty(&self) -> bool

Returns whether number of array slots is zero

impl<K> Debug for FixedSizeBinaryDictionaryBuilder<K>

where K: ArrowDictionaryKeyType + Debug,

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

Formats the value using the given formatter.