[−][src]Struct arrow::array::DictionaryArray
A dictionary array where each element is a single value indexed by an integer key. This is mostly used to represent strings or a limited set of primitive types as integers, for example when doing NLP analysis or representing chromosomes by name.
Example with nullable data:
use arrow::array::{DictionaryArray, Int8Array}; use arrow::datatypes::Int8Type; let test = vec!["a", "a", "b", "c"]; let array : DictionaryArray<Int8Type> = test.iter().map(|&x| if x == "b" {None} else {Some(x)}).collect(); assert_eq!(array.keys(), &Int8Array::from(vec![Some(0), Some(0), None, Some(1)]));
Example without nullable data:
use arrow::array::{DictionaryArray, Int8Array}; use arrow::datatypes::Int8Type; let test = vec!["a", "a", "b", "c"]; let array : DictionaryArray<Int8Type> = test.into_iter().collect(); assert_eq!(array.keys(), &Int8Array::from(vec![0, 0, 1, 2]));
Implementations
impl<'a, K: ArrowPrimitiveType> DictionaryArray<K>
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pub fn keys(&self) -> &PrimitiveArray<K>
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Return an iterator to the keys of this dictionary.
pub fn keys_array(&self) -> PrimitiveArray<K>
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Returns an array view of the keys of this dictionary
pub fn lookup_key(&self, value: &str) -> Option<K::Native>
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Returns the lookup key by doing reverse dictionary lookup
pub fn values(&self) -> ArrayRef
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Returns an ArrayRef
to the dictionary values.
pub fn value_type(&self) -> DataType
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Returns a clone of the value type of this list.
pub fn len(&self) -> usize
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The length of the dictionary is the length of the keys array.
pub fn is_empty(&self) -> bool
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Whether this dictionary is empty
pub fn is_ordered(&self) -> bool
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Trait Implementations
impl<T: ArrowPrimitiveType> Array for DictionaryArray<T>
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fn as_any(&self) -> &dyn Any
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fn data(&self) -> ArrayDataRef
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fn data_ref(&self) -> &ArrayDataRef
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fn get_buffer_memory_size(&self) -> usize
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fn get_array_memory_size(&self) -> usize
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fn data_type(&self) -> &DataType
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fn slice(&self, offset: usize, length: usize) -> ArrayRef
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fn len(&self) -> usize
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fn is_empty(&self) -> bool
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fn offset(&self) -> usize
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fn is_null(&self, index: usize) -> bool
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fn is_valid(&self, index: usize) -> bool
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fn null_count(&self) -> usize
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fn to_raw(&self) -> Result<(*const FFI_ArrowArray, *const FFI_ArrowSchema)>
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impl<T: ArrowPrimitiveType> Debug for DictionaryArray<T>
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impl<T: ArrowPrimitiveType> From<Arc<ArrayData>> for DictionaryArray<T>
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Constructs a DictionaryArray
from an array data reference.
fn from(data: ArrayDataRef) -> Self
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impl<'a, T: ArrowPrimitiveType + ArrowDictionaryKeyType> FromIterator<&'a str> for DictionaryArray<T>
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Constructs a DictionaryArray
from an iterator of strings.
fn from_iter<I: IntoIterator<Item = &'a str>>(iter: I) -> Self
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impl<'a, T: ArrowPrimitiveType + ArrowDictionaryKeyType> FromIterator<Option<&'a str>> for DictionaryArray<T>
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Constructs a DictionaryArray
from an iterator of optional strings.
fn from_iter<I: IntoIterator<Item = Option<&'a str>>>(iter: I) -> Self
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impl<T: ArrowPrimitiveType> JsonEqual for DictionaryArray<T>
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fn equals_json(&self, json: &[&Value]) -> bool
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fn equals_json_values(&self, json: &[Value]) -> bool
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impl<T: ArrowPrimitiveType> PartialEq<Value> for DictionaryArray<T>
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Auto Trait Implementations
impl<K> !RefUnwindSafe for DictionaryArray<K>
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impl<K> Send for DictionaryArray<K>
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impl<K> Sync for DictionaryArray<K>
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impl<K> Unpin for DictionaryArray<K>
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impl<K> !UnwindSafe for DictionaryArray<K>
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Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,