Trait FieldExt 

pub trait FieldExt {
    // Required methods
    fn into_list(self) -> Self;
    fn into_fixed_size_list(self, list_size: i32) -> Self;
    fn into_list_item(self) -> Self;
}

DataFusion extension methods for Arrow Field and FieldRef

Required Methods

fn into_list(self) -> Self

Returns a new Field representing a List of this Field’s DataType.

For example if input represents an Int32, the return value will represent a List<Int32>.

Example:

// Int32 field
let int_field = Field::new("my_int", DataType::Int32, true);
// convert to a List field
let list_field = int_field.into_list();
// List<Int32>
// Note that the item field name has been renamed to "item"
assert_eq!(list_field.data_type(), &DataType::List(Arc::new(
    Field::new("item", DataType::Int32, true)
)));

fn into_fixed_size_list(self, list_size: i32) -> Self

Return a new Field representing this Field as the item type of a DataType::FixedSizeList

For example if input represents an Int32, the return value will represent a FixedSizeList<Int32, size>.

Example:

// Int32 field
let int_field = Field::new("my_int", DataType::Int32, true);
// convert to a FixedSizeList field of size 3
let fixed_size_list_field = int_field.into_fixed_size_list(3);
// FixedSizeList<Int32, 3>
// Note that the item field name has been renamed to "item"
assert_eq!(
  fixed_size_list_field.data_type(),
  &DataType::FixedSizeList(Arc::new(
   Field::new("item", DataType::Int32, true)),
   3
));

fn into_list_item(self) -> Self

Update the field to have the default list field name (“item”)

Lists are allowed to have an arbitrarily named field; however, a name other than ‘item’ will cause it to fail an == check against a more idiomatically created list in arrow-rs which causes issues.

For example, if input represents an Int32 field named “my_int”, the return value will represent an Int32 field named “item”.

Example:

let my_field = Field::new("my_int", arrow::datatypes::DataType::Int32, true);
let item_field = my_field.into_list_item();
assert_eq!(item_field.name(), Field::LIST_FIELD_DEFAULT_NAME);
assert_eq!(item_field.name(), "item");

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl FieldExt for Arc<Field>

fn into_list(self) -> Self

fn into_fixed_size_list(self, list_size: i32) -> Self

fn into_list_item(self) -> Self

impl FieldExt for Field

fn into_list(self) -> Self

fn into_fixed_size_list(self, list_size: i32) -> Self

fn into_list_item(self) -> Self

Implementors