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numojo.core.indexing.item

Item (numojo.core.indexing.item)

Implements Item type.

Item is a series of Int on the heap used to index into N-dimensional arrays. It is used for multi-dimensional indexing, such as arr[Item(1, 2, 3)] to access arr[1, 2, 3].

Structs

Item

struct Item

Memory convention: register_passable
Implements: AnyType, Copyable, Equatable, ImplicitlyCopyable, ImplicitlyDestructible, Movable, RegisterPassable, Representable, Sized, Stringable, Writable

Represents a multi-dimensional index for array access.

The Item struct is used to specify the coordinates of an element within an N-dimensional array. For example, arr[Item(1, 2, 3)] retrieves the element at position (1, 2, 3) in a 3D array.

Each Item instance holds a sequence of integer indices, one for each dimension of the array. This allows for precise and flexible indexing into arrays of arbitrary dimensionality.

Example: 

from numojo.prelude import *
import numojo as nm
var arr = nm.arange[f32](0, 27).reshape(Shape(3, 3, 3))
var value = arr[Item(1, 2, 3)]  # Accesses arr[1, 2, 3]

Fields

  • ndim (Int): Number of dimensions (length of the index tuple).

Aliases

element_type
comptime element_type

Value: DType.int

The data type of the Item elements.

__del__is_trivial
comptime __del__is_trivial

Value: False

__move_ctor_is_trivial
comptime __move_ctor_is_trivial

Value: True

__copy_ctor_is_trivial
comptime __copy_ctor_is_trivial

Value: False

Methods

__init__
Overload 1
__init__() -> Self

static

Initializes an empty Item.

Returns:

  • Self
Overload 2
__init__(buf: IndexBuffer) -> Self

static

Initializes the Item from an IndexBuffer.

Args:

  • buf (IndexBuffer): The IndexBuffer to initialize from.

Returns:

  • Self
Overload 3
__init__[T: Indexer](*args: T) -> Self

static

Construct the Item with variable arguments.

Parameters:

  • T (Indexer): Type of values. It can be converted to Int with Int().

Args:

  • *args (T): Initial values.

Returns:

  • Self
Overload 4
__init__[T: IndexerCollectionElement](args: List[T]) -> Self

static

Construct the Item from a list.

Parameters:

  • T (IndexerCollectionElement): Type of values. It can be converted to Int with Int().

Args:

  • args (List): Initial values.

Returns:

  • Self
Overload 5
__init__(args: List[Int]) -> Self

static

Construct the Item from a list.

Args:

  • args (List): Initial values.

Returns:

  • Self
Overload 6
__init__(args: VariadicList[Int]) -> Self

static

Construct the Item from a variadic list.

Args:

  • args (VariadicList): Initial values.

Returns:

  • Self
Overload 7
__init__(*, ndim: Int) -> Self

static

Construct the Item with given length and initialize to zero.

Args:

  • ndim (Int): The length of the Item.

Returns:

  • Self
Overload 8
__init__(*, copy: Self) -> Self

static

Copy construct the Item.

Args:

  • copy (Self): The Item to copy.

Returns:

  • Self
__getitem__
Overload 1
__getitem__(self, idx: Int) -> Int

Gets the value at the specified index.

Args:

  • self (Self)
  • idx (Int): The index of the value to get.

Returns:

  • Int

Raises

Error: If index is out of range.

Overload 2
__getitem__(self, slice_index: Slice) -> Self

Return a sliced view of the item as a new Item.

Args:

  • self (Self)
  • slice_index (Slice): Slice object defining the sub-buffer.

Returns:

  • Self

Raises

__setitem__
__setitem__(mut self, idx: Int, val: Int)

Set the value at the specified index.

Args:

  • self (Self) [mut]
  • idx (Int): The index of the value to set.
  • val (Int): The value to set.

Raises

Error: If index is out of range.

__eq__
__eq__(self, other: Self) -> Bool

Checks if two items have identical dimensions and values.

Args:

  • self (Self)
  • other (Self): The item to compare with.

Returns:

  • Bool
__ne__
__ne__(self, other: Self) -> Bool

Checks if two items have different dimensions or values.

Args:

  • self (Self)
  • other (Self): The item to compare with.

Returns:

  • Bool
__contains__
Overload 1
__contains__(self, val: Scalar[DType.int]) -> Bool

Check if the Item contains the given value.

Args:

  • self (Self)
  • val (Scalar): Value to check for.

Returns:

  • Bool
Overload 2
__contains__(self, val: Int) -> Bool

Checks if the given value is present in the item.

Args:

  • self (Self)
  • val (Int): The value to search for.

Returns:

  • Bool
load
load[width: Int = 1](self, idx: Int) -> SIMD[DType.int, width]

Load a SIMD vector from the Item at the specified index.

Parameters:

  • width (Int): The width of the SIMD vector.

Args:

  • self (Self)
  • idx (Int): The starting index to load from.

Returns:

  • SIMD

Raises

Error: If the load exceeds the bounds of the Item.

store
store[width: Int = 1](self, idx: Int, value: SIMD[DType.int, width])

Store a SIMD vector into the Item at the specified index.

Parameters:

  • width (Int): The width of the SIMD vector.

Args:

  • self (Self)
  • idx (Int): The starting index to store to.
  • value (SIMD): The SIMD vector to store.

Raises

Error: If the store exceeds the bounds of the Item.

unsafe_load
unsafe_load[width: Int = 1](self, idx: Int) -> SIMD[DType.int, width]

Unsafely load a SIMD vector from the Item at the specified index.

Parameters:

  • width (Int): The width of the SIMD vector.

Args:

  • self (Self)
  • idx (Int): The starting index to load from.

Returns:

  • SIMD
unsafe_store
unsafe_store[width: Int = 1](self, idx: Int, value: SIMD[DType.int, width])

Unsafely store a SIMD vector into the Item at the specified index.

Parameters:

  • width (Int): The width of the SIMD vector.

Args:

  • self (Self)
  • idx (Int): The starting index to store to.
  • value (SIMD): The SIMD vector to store.
swapaxes
swapaxes(self, axis1: Int, axis2: Int) -> Self

Returns a new item with the given axes swapped.

Args:

  • self (Self)
  • axis1 (Int): The first axis to swap.
  • axis2 (Int): The second axis to swap.

Returns:

  • Self

Raises

join
join(self, *others: Self) -> Self

Join multiple items into a single item.

Args:

  • self (Self)
  • *others (Self): Variable number of Item objects.

Returns:

  • Self
extend
extend(self, *values: Int) -> Self

Extend the shape by sizes of extended dimensions.

Args:

  • self (Self)
  • *values (Int): Sizes of extended dimensions.

Returns:

  • Self
flip
flip(mut self)

Flip the items in-place.

Args:

  • self (Self) [mut]
flipped
flipped(self) -> Self

Returns a new item by flipping the items.

Args:

  • self (Self)

Returns:

  • Self
move_axis_to_end
move_axis_to_end(self, axis: Int) -> Self

Returns a new item by moving the value of axis to the end.

Args:

  • self (Self)
  • axis (Int): The axis (index) to move.

Returns:

  • Self
pop
pop(self, axis: Int) -> Self

Drops information of certain axis.

Args:

  • self (Self)
  • axis (Int): The axis (index) to drop.

Returns:

  • Self

Raises

rank
rank(self) -> Int

Returns the number of dimensions of the Item.

Args:

  • self (Self)

Returns:

  • Int
sum
sum(self) -> Scalar[DType.int]

Compute the sum of all elements in Item.

Args:

  • self (Self)

Returns:

  • Scalar
product
product(self) -> Scalar[DType.int]

Compute the product of all elements in the Item.

Args:

  • self (Self)

Returns:

  • Scalar
__len__
__len__(self) -> Int

Get the length of the Item.

Args:

  • self (Self)

Returns:

  • Int
__repr__
__repr__(self) -> String

Returns a string representation of the Item.

Args:

  • self (Self)

Returns:

  • String
__str__
__str__(self) -> String

Returns a string representation of the Item.

Args:

  • self (Self)

Returns:

  • String
write_to
write_to[W: Writer](self, mut writer: W)

Writes the Item representation to a writer.

Parameters:

  • W (Writer)

Args:

  • self (Self)
  • writer (W) [mut]
tolist
tolist(self) -> List[Int]

Convert the Item to a list of integers.

Args:

  • self (Self)

Returns:

  • List
normalize_index
normalize_index(self, index: Int) -> Int

Normalizes the given index to be within the valid range [0, ndim).

Args:

  • self (Self)
  • index (Int): The index to normalize.

Returns:

  • Int
__iter__
__iter__(ref self) -> _ItemIter[origin_of(self)]

Iterate over elements of the Item.

Args:

  • self (Self) [ref]

Returns:

  • _ItemIter
__reversed__
__reversed__(ref self) -> _ItemIter[origin_of(self), False]

Iterate over elements of the Item in reverse.

Args:

  • self (Self) [ref]

Returns:

  • _ItemIter