Trait Length 

pub trait Length {
    // Required method
    fn len(&self) -> usize;

    // Provided method
    fn is_empty(&self) -> bool { ... }
}

The length (or number of elements) of a collection.

Required Methods

fn len(&self) -> usize

Returns the number of elements in the collection, also referred to as its length.

Provided Methods

fn is_empty(&self) -> bool

Returns true if there are no elements in the collection.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl Length for &str

fn len(&self) -> usize

impl Length for BooleanBuffer

Available on crate feature arrow-rs only.

fn len(&self) -> usize

impl Length for NullBuffer

Available on crate feature arrow-rs only.

fn len(&self) -> usize

impl Length for String

fn len(&self) -> usize

impl<T: FixedSize> Length for BufferBuilder<T>

Available on crate feature arrow-rs only.

fn len(&self) -> usize

impl<T: FixedSize> Length for ScalarBuffer<T>

Available on crate feature arrow-rs only.

fn len(&self) -> usize

impl<T: Length> Length for Option<T>

fn len(&self) -> usize

impl<T> Length for &[T]

fn len(&self) -> usize

impl<T> Length for &mut [T]

fn len(&self) -> usize

impl<T> Length for Arc<[T]>

fn len(&self) -> usize

impl<T> Length for Box<[T]>

fn len(&self) -> usize

impl<T> Length for IntoIter<T>

fn len(&self) -> usize

impl<T> Length for Iter<'_, T>

fn len(&self) -> usize

impl<T> Length for Rc<[T]>

fn len(&self) -> usize

impl<T> Length for Vec<T>

fn len(&self) -> usize

impl<T> Length for VecDeque<T>

fn len(&self) -> usize

impl<T> Length for [T]

fn len(&self) -> usize

impl<const N: usize, T> Length for [T; N]

fn len(&self) -> usize

Implementors

impl Length for VariableSizeBinary

impl<Buffer: BufferType> Length for Bitmap<Buffer>

impl<K: ArrayType<K>, V: ArrayType<V>, Buffer: BufferType> Length for KeyValueArray<K, V, Buffer>

where <K as ArrayType<K>>::Array<Buffer, NA, NA>: Length, <V as ArrayType<V>>::Array<Buffer, NA, NA>: Length,

Available on crate feature map only.

impl<Nullable: Nullability, Buffer: BufferType> Length for BooleanArray<Nullable, Buffer>

where Nullable::Collection<Bitmap<Buffer>, Buffer>: Length,

impl<Nullable: Nullability, OffsetItem: Offset, Buffer: BufferType> Length for StringArray<Nullable, OffsetItem, Buffer>

where VariableSizeBinaryArray<Nullable, OffsetItem, Buffer>: Length,

impl<Nullable: Nullability, OffsetItem: Offset, Buffer: BufferType> Length for VariableSizeBinaryArray<Nullable, OffsetItem, Buffer>

where Offsets<FixedSizePrimitiveArray<u8, NonNullable, Buffer>, Nullable, OffsetItem, Buffer>: Length,

impl<T, Nulls: Nullability, OffsetItem: Offset, Buffer: BufferType> Length for OffsetSlice<'_, T, Nulls, OffsetItem, Buffer>

impl<T, OffsetItem: Offset, Buffer: BufferType> Length for Offsets<T, NonNullable, OffsetItem, Buffer>

impl<T, OffsetItem: Offset, Buffer: BufferType> Length for Offsets<T, Nullable, OffsetItem, Buffer>

impl<T: Array, Nullable: Nullability, OffsetItem: Offset, Buffer: BufferType> Length for VariableSizeListArray<T, Nullable, OffsetItem, Buffer>

where Offsets<T, Nullable, OffsetItem, Buffer>: Length,

impl<T: FixedSize, Nullable: Nullability, Buffer: BufferType> Length for FixedSizePrimitiveArray<T, Nullable, Buffer>

where Nullable::Collection<Buffer::Buffer<T>, Buffer>: Length,

impl<T: LogicalArrayType<T>, Nullable: Nullability, Buffer: BufferType, OffsetItem: Offset, UnionLayout: UnionType> Length for LogicalArray<T, Nullable, Buffer, OffsetItem, UnionLayout>

where Option<T>: ArrayType<T>, Nullable::Item<T::ArrayType>: ArrayType<T::ArrayType>, <Nullable::Item<T::ArrayType> as ArrayType<T::ArrayType>>::Array<Buffer, OffsetItem, UnionLayout>: Length,

impl<T: StructArrayType, Nullable: Nullability, Buffer: BufferType> Length for StructArray<T, Nullable, Buffer>

where Nullable::Collection<<T as StructArrayType>::Array<Buffer>, Buffer>: Length,

impl<T: UnionArrayType<VARIANTS>, const VARIANTS: usize, Buffer: BufferType, OffsetItem: Offset> Length for DenseUnionArray<T, VARIANTS, Buffer, OffsetItem>

where for<'a> i8: From<&'a T>,

impl<T: UnionArrayType<VARIANTS>, const VARIANTS: usize, Buffer: BufferType, OffsetItem: Offset> Length for SparseUnionArray<T, VARIANTS, Buffer, OffsetItem>

where for<'a> i8: From<&'a T>,

impl<T: UnionArrayType<VARIANTS>, const VARIANTS: usize, UnionLayout: UnionType, Buffer: BufferType, OffsetItem: Offset> Length for UnionArray<T, VARIANTS, UnionLayout, Buffer, OffsetItem>

where for<'a> i8: From<&'a T>, <UnionLayout as UnionType>::Array<T, VARIANTS, Buffer, OffsetItem>: Length,

impl<T: Unit, Nullable: Nullability, Buffer: BufferType> Length for NullArray<T, Nullable, Buffer>

where Nullable::Collection<Nulls<T>, Buffer>: Length,

impl<T: Unit> Length for Nulls<T>

impl<const N: usize, Nullable: Nullability, Buffer: BufferType> Length for FixedSizeBinaryArray<N, Nullable, Buffer>

where FixedSizeListArray<N, FixedSizePrimitiveArray<u8, NonNullable, Buffer>, Nullable, Buffer>: Length,

impl<const N: usize, T: Array, Nullable: Nullability, Buffer: BufferType> Length for FixedSizeListArray<N, T, Nullable, Buffer>

where Nullable::Collection<T, Buffer>: Length,