Trait AnyDictionaryArray
pub trait AnyDictionaryArray: Array {
// Required methods
fn keys(&self) -> &dyn Array;
fn values(&self) -> &Arc<dyn Array>;
fn normalized_keys(&self) -> Vec<usize>;
fn with_values(&self, values: Arc<dyn Array>) -> Arc<dyn Array>;
}Expand description
A DictionaryArray with the key type erased
This can be used to efficiently implement kernels for all possible dictionary keys without needing to create specialized implementations for each key type
For example
fn to_string(a: &dyn Array) -> Result<ArrayRef, ArrowError> {
if let Some(d) = a.as_any_dictionary_opt() {
// Recursively handle dictionary input
let r = to_string(d.values().as_ref())?;
return Ok(d.with_values(r));
}
downcast_primitive_array! {
a => Ok(Arc::new(a.iter().map(|x| x.map(|x| format!("{x:?}"))).collect::<StringArray>())),
d => Err(ArrowError::InvalidArgumentError(format!("{d:?} not supported")))
}
}
let result = to_string(&Int32Array::from(vec![1, 2, 3])).unwrap();
let actual = result.as_string::<i32>().iter().map(Option::unwrap).collect::<Vec<_>>();
assert_eq!(actual, &["1", "2", "3"]);
let mut dict = PrimitiveDictionaryBuilder::<Int32Type, UInt16Type>::new();
dict.extend([Some(1), Some(1), Some(2), Some(3), Some(2)]);
let dict = dict.finish();
let r = to_string(&dict).unwrap();
let r = r.as_dictionary::<Int32Type>().downcast_dict::<StringArray>().unwrap();
assert_eq!(r.keys(), dict.keys()); // Keys are the same
let actual = r.into_iter().map(Option::unwrap).collect::<Vec<_>>();
assert_eq!(actual, &["1", "1", "2", "3", "2"]);See AsArray::as_any_dictionary_opt and AsArray::as_any_dictionary
Required Methods§
fn normalized_keys(&self) -> Vec<usize>
fn normalized_keys(&self) -> Vec<usize>
Returns the keys of this dictionary as usize
The values for nulls will be arbitrary, but are guaranteed
to be in the range 0..self.values.len()
§Panic
Panics if values.len() == 0
fn with_values(&self, values: Arc<dyn Array>) -> Arc<dyn Array>
fn with_values(&self, values: Arc<dyn Array>) -> Arc<dyn Array>
Create a new DictionaryArray replacing values with the new values