Struct arrow_array::builder::GenericByteDictionaryBuilder

pub struct GenericByteDictionaryBuilder<K, T>
where
    K: ArrowDictionaryKeyType,
    T: ByteArrayType,
{ /* private fields */ }

Builder for DictionaryArray of GenericByteArray

For example to map a set of byte indices to String values. Note that the use of a HashMap here will not scale to very large arrays or result in an ordered dictionary.

Implementations

impl<K, T> GenericByteDictionaryBuilder<K, T>

where K: ArrowDictionaryKeyType, T: ByteArrayType,

pub fn new() -> Self

Creates a new GenericByteDictionaryBuilder

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

Creates a new GenericByteDictionaryBuilder 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 data_capacity: the total number of bytes of all distinct bytes in the dictionary

pub fn new_with_dictionary( keys_capacity: usize, dictionary_values: &GenericByteArray<T>, ) -> Result<Self, ArrowError>

Creates a new GenericByteDictionaryBuilder from a keys capacity and a dictionary which is initialized with the given values. The indices of those dictionary values are used as keys.

Example

let dictionary_values = StringArray::from(vec![None, Some("abc"), Some("def")]);

let mut builder = StringDictionaryBuilder::new_with_dictionary(3, &dictionary_values).unwrap();
builder.append("def").unwrap();
builder.append_null();
builder.append("abc").unwrap();

let dictionary_array = builder.finish();

let keys = dictionary_array.keys();

assert_eq!(keys, &Int16Array::from(vec![Some(2), None, Some(1)]));

impl<K, T> GenericByteDictionaryBuilder<K, T>

where K: ArrowDictionaryKeyType, T: ByteArrayType,

pub fn append( &mut self, value: impl AsRef<T::Native>, ) -> 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_n( &mut self, value: impl AsRef<T::Native>, count: usize, ) -> Result<K::Native, ArrowError>

Append a value multiple times to the array. This is the same as append but allows to append the same value multiple times without doing multiple lookups.

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

pub fn append_value(&mut self, value: impl AsRef<T::Native>)

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 append_values(&mut self, value: impl AsRef<T::Native>, count: usize)

Infallibly append a value to this builder repeatedly count times. This is the same as append_value but allows to append the same value multiple times without doing multiple lookups.

Panics

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

pub fn append_null(&mut self)

Appends a null slot into the builder

pub fn append_nulls(&mut self, n: usize)

Infallibly append n null slots into the builder

pub fn append_option(&mut self, value: Option<impl AsRef<T::Native>>)

Append an Option value into the builder

Panics

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

pub fn append_options( &mut self, value: Option<impl AsRef<T::Native>>, count: usize, )

Append an Option value into the builder repeatedly count times. This is the same as append_option but allows to append the same value multiple times without doing multiple lookups.

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.

pub fn validity_slice(&self) -> Option<&[u8]>

Returns the current null buffer as a slice

Trait Implementations

impl<K, T> ArrayBuilder for GenericByteDictionaryBuilder<K, T>

where K: ArrowDictionaryKeyType, T: ByteArrayType,

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, T> Debug for GenericByteDictionaryBuilder<K, T>

where K: ArrowDictionaryKeyType + Debug, T: ByteArrayType + Debug,

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

Formats the value using the given formatter.

impl<K, T> Default for GenericByteDictionaryBuilder<K, T>

where K: ArrowDictionaryKeyType, T: ByteArrayType,

fn default() -> Self

Returns the “default value” for a type.

impl<K: ArrowDictionaryKeyType, T: ByteArrayType, V: AsRef<T::Native>> Extend<Option<V>> for GenericByteDictionaryBuilder<K, T>

fn extend<I: IntoIterator<Item = Option<V>>>(&mut self, iter: I)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.