Struct UnionFields 

pub struct UnionFields(Arc<[(i8, FieldRef)]>);

A cheaply cloneable, owned collection of FieldRef and their corresponding type ids

Tuple Fields

0: Arc<[(i8, FieldRef)]>

Implementations

impl UnionFields

pub fn empty() -> Self

Create a new UnionFields with no fields

pub fn new<F, T>(type_ids: T, fields: F) -> Self

where F: IntoIterator, F::Item: Into<FieldRef>, T: IntoIterator<Item = i8>,

Create a new UnionFields from a Fields and array of type_ids

See https://arrow.apache.org/docs/format/Columnar.html#union-layout

use arrow_schema::{DataType, Field, UnionFields};
// Create a new UnionFields with type id mapping
// 1 -> DataType::UInt8
// 3 -> DataType::Utf8
UnionFields::new(
    vec![1, 3],
    vec![
        Field::new("field1", DataType::UInt8, false),
        Field::new("field3", DataType::Utf8, false),
    ],
);

pub fn size(&self) -> usize

Return size of this instance in bytes.

pub fn len(&self) -> usize

Returns the number of fields in this UnionFields

pub fn is_empty(&self) -> bool

Returns true if this is empty

pub fn iter(&self) -> impl Iterator<Item = (i8, &FieldRef)> + '_

Returns an iterator over the fields and type ids in this UnionFields

pub fn get(&self, index: usize) -> Option<&(i8, FieldRef)>

Returns a reference to the field at the given index, or None if out of bounds.

This is a safe alternative to direct indexing via [].

Example

use arrow_schema::{DataType, Field, UnionFields};

let fields = UnionFields::new(
    vec![1, 3],
    vec![
        Field::new("field1", DataType::UInt8, false),
        Field::new("field3", DataType::Utf8, false),
    ],
);

assert!(fields.get(0).is_some());
assert!(fields.get(1).is_some());
assert!(fields.get(2).is_none());

pub fn find_by_type_id(&self, type_id: i8) -> Option<(i8, &FieldRef)>

Searches for a field by its type id, returning the type id and field reference if found. Returns None if no field with the given type id exists.

pub fn find_by_field(&self, field: &Field) -> Option<(i8, &FieldRef)>

Searches for a field by value equality, returning its type id and reference if found. Returns None if no matching field exists in this UnionFields.

pub(crate) fn try_merge(&mut self, other: &Self) -> Result<(), ArrowError>

Merge this field into self if it is compatible.

See Field::try_merge

Trait Implementations

impl Clone for UnionFields

fn clone(&self) -> UnionFields

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UnionFields

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for UnionFields

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl FromIterator<(i8, Arc<Field>)> for UnionFields

fn from_iter<T: IntoIterator<Item = (i8, FieldRef)>>(iter: T) -> Self

Creates a value from an iterator.

impl Hash for UnionFields

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Index<usize> for UnionFields

Allows direct indexing into UnionFields to access fields by position.

Panics

Panics if the index is out of bounds. Note that UnionFields supports a maximum of 128 fields, as type IDs are represented as i8 values.

For a non-panicking alternative, use UnionFields::get.

type Output = (i8, Arc<Field>)

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl Ord for UnionFields

fn cmp(&self, other: &UnionFields) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for UnionFields

fn eq(&self, other: &UnionFields) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for UnionFields

fn partial_cmp(&self, other: &UnionFields) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for UnionFields

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for UnionFields

impl StructuralPartialEq for UnionFields