Struct arrow_array::builder::PrimitiveDictionaryBuilder

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pub struct PrimitiveDictionaryBuilder<K, V>where
    K: ArrowPrimitiveType,
    V: ArrowPrimitiveType,
{ /* private fields */ }

Expand description

Builder for DictionaryArray of PrimitiveArray

§Example:



let mut builder = PrimitiveDictionaryBuilder::<UInt8Type, UInt32Type>::new();
 builder.append(12345678).unwrap();
 builder.append_null();
 builder.append(22345678).unwrap();
 let array = builder.finish();

 assert_eq!(
     array.keys(),
     &UInt8Array::from(vec![Some(0), None, Some(1)])
 );

 // Values are polymorphic and so require a downcast.
 let av = array.values();
 let ava: &UInt32Array = av.as_any().downcast_ref::<UInt32Array>().unwrap();
 let avs: &[u32] = ava.values();

 assert!(!array.is_null(0));
 assert!(array.is_null(1));
 assert!(!array.is_null(2));

 assert_eq!(avs, &[12345678, 22345678]);

Implementations§

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impl<K, V> PrimitiveDictionaryBuilder<K, V>
where K: ArrowPrimitiveType, V: ArrowPrimitiveType,

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pub fn new() -> Self

Creates a new PrimitiveDictionaryBuilder.

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pub fn new_from_empty_builders( keys_builder: PrimitiveBuilder<K>, values_builder: PrimitiveBuilder<V>, ) -> Self

Creates a new PrimitiveDictionaryBuilder from the provided keys and values builders.

§Panics

This method panics if keys_builder or values_builder is not empty.

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pub unsafe fn new_from_builders( keys_builder: PrimitiveBuilder<K>, values_builder: PrimitiveBuilder<V>, ) -> Self

Creates a new PrimitiveDictionaryBuilder from existing PrimitiveBuilders of keys and values.

§Safety

caller must ensure that the passed in builders are valid for DictionaryArray.

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

Creates a new PrimitiveDictionaryBuilder with the provided capacities

keys_capacity: the number of keys, i.e. length of array to build values_capacity: the number of distinct dictionary values, i.e. size of dictionary

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impl<K, V> PrimitiveDictionaryBuilder<K, V>
where K: ArrowDictionaryKeyType, V: ArrowPrimitiveType,

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pub fn append(&mut self, value: V::Native) -> Result<K::Native, ArrowError>

Append a primitive 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.

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pub fn append_n( &mut self, value: V::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.

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pub fn append_value(&mut self, value: V::Native)

Infallibly append a value to this builder

§Panics

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

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pub fn append_values(&mut self, value: V::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

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pub fn append_null(&mut self)

Appends a null slot into the builder

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

Append n null slots into the builder

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pub fn append_option(&mut self, value: Option<V::Native>)

Append an Option value into the builder

§Panics

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

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pub fn append_options(&mut self, value: Option<V::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.