Struct Array 

pub struct Array { /* private fields */ }

A column of values, in Arrow’s layout.

Implementations

impl Array

pub fn of(vector: &Vector) -> Result<Self>

The Arrow array a vector becomes.

The vector is flattened first, so a constant, a sequence and a dictionary all arrive here as the values they stand for. Arrow has a run end encoding and a dictionary array of its own and they are worth having later, but an export that sometimes hands back a dictionary is an export every reader has to have two paths for, and the reader is the one we are trying to make cheap.

Errors

For a type with no Arrow counterpart, and for a vector whose values are not the layout its type says they are.

pub fn empty(data_type: DataType) -> Self

An array of this type with no values in it.

A variable width type still gets its offsets buffer, holding the single zero that says the first value would start at the beginning. Arrow’s rule is that offsets are one longer than the array, and an array of nothing is the case where forgetting it is easiest and where a reader that trusts the rule reads past the end.

pub fn data_type(&self) -> &DataType

What the column holds.

pub fn len(&self) -> usize

How many values.

pub fn is_empty(&self) -> bool

Whether there are none.

pub fn null_count(&self) -> usize

How many of them are null.

pub fn validity(&self) -> Option<&[u8]>

The validity bitmap, or nothing when nothing is null.

Nothing is what Arrow means by a null pointer in the first buffer slot, and it is the case worth keeping rather than materializing: a reader that sees it can skip the per value check for the whole array, which is the same reason Validity::AllValid exists on our side.

pub fn offsets(&self) -> Option<&[u8]>

The offsets buffer, for the variable width types, as little endian i32.

pub fn values(&self) -> &[u8]

The values buffer.

pub fn buffers(&self) -> Vec<Option<&[u8]>>

The buffers in the order the C data interface lists them.

Two or three of them, and which is which is the type’s business rather than the caller’s, which is why this exists next to the three accessors above.

Trait Implementations

impl Clone for Array

fn clone(&self) -> Array

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Array

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

Formats the value using the given formatter.

impl Eq for Array

impl PartialEq for Array

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Array