Struct StructFields 

pub struct StructFields(/* private fields */);

Type information for a struct column.

The StructFields holds all field names and field types, and provides access to them by index or by name.

Duplicate field names

In memory, it is not an error for a StructFields to contain duplicate field names. In that case, any name-based access to fields will resolve to the first such field with a given name.

let fields = StructFields::from_iter([
    ("string_col", DType::Utf8(Nullability::NonNullable)),
    ("binary_col", DType::Binary(Nullability::NonNullable)),
    ("int_col", DType::Primitive(PType::I32, Nullability::Nullable)),
    ("int_col", DType::Primitive(PType::I64, Nullability::Nullable)),
]);

// Accessing a field by name will yield the first
assert_eq!(fields.field("int_col").unwrap(), DType::Primitive(PType::I32, Nullability::Nullable));

Implementations

impl StructFields

pub fn empty() -> Self

The fields of the empty struct.

pub fn new(names: FieldNames, dtypes: Vec<DType>) -> Self

Create a new StructFields from a list of names and dtypes

pub fn from_fields(names: FieldNames, dtypes: Vec<FieldDType>) -> Self

Create a new StructFields from a list of names and FieldDType which can be either lazily or eagerly serialized.

pub fn names(&self) -> &FieldNames

Get the names of the fields in the struct

pub fn nfields(&self) -> usize

Returns the number of fields in the struct

pub fn field_name(&self, index: usize) -> Option<&FieldName>

Returns the name of the field at the given index

pub fn find(&self, name: impl AsRef<str>) -> Option<usize>

Find the index of a field by name Returns None if the field is not found

pub fn field(&self, name: impl AsRef<str>) -> Option<DType>

Get the DType of a field.

It is possible for there to be more than one field with the same name, in which case, this will return the DType of the first field encountered with a given name.

pub fn field_by_index(&self, index: usize) -> Option<DType>

Get the DType of a field by index.

pub fn fields(&self) -> impl ExactSizeIterator<Item = DType> + '_

Returns an ordered iterator over the fields.

pub fn project(&self, projection: &[FieldName]) -> VortexResult<Self>

Project a subset of fields from the struct

If any of the fields are not found, this method will return an error.

pub fn without_field(&self, index: usize) -> VortexResult<Self>

Returns a new StructFields without the field at the given index.

Errors

Returns an error if the index is out of bounds for the struct fields.

pub fn disjoint_merge(&self, other: &Self) -> VortexResult<Self>

Merge two StructFields instances into a new one. Order of fields in arguments is preserved

Errors

Returns an error if the merged struct would have duplicate field names.

Trait Implementations

impl Clone for StructFields

fn clone(&self) -> StructFields

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for StructFields

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

Formats the value using the given formatter.

impl Default for StructFields

fn default() -> Self

Returns the “default value” for a type.

impl Display for StructFields

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

Formats the value using the given formatter.

impl FromArrowType<&Fields> for StructFields

fn from_arrow(value: &Fields) -> Self

Convert the Arrow type to a Vortex type.

impl<T, V> FromIterator<(T, V)> for StructFields

where T: Into<FieldName>, V: Into<FieldDType>,

fn from_iter<I: IntoIterator<Item = (T, V)>>(iter: I) -> Self

Creates a value from an iterator.

impl Hash for StructFields

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 PartialEq for StructFields

fn eq(&self, other: &StructFields) -> 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 Eq for StructFields

impl StructuralPartialEq for StructFields