Table of Contents

Class np.NDEnumerate

Namespace
NumSharp
Assembly
NumSharp.dll

NumPy's numpy.ndenumerate — walks an array in C-order, yielding (index, value) for every element.

// numpy: list(np.ndenumerate(np.array([[1, 2], [3, 4]])))
//     -> [((0,0), 1), ((0,1), 2), ((1,0), 3), ((1,1), 4)]
foreach (var (index, value) in np.ndenumerate(a)) { … }

Like NumPy the object is its OWN iterator (iter(e) is e): it keeps a single live cursor, so a second enumeration resumes where the first stopped.

public class np.NDEnumerate : IEnumerable<(long[] index, object value)>, IEnumerable, IEnumerator<(long[] index, object value)>, IEnumerator, IDisposable
Inheritance
np.NDEnumerate
Implements
Inherited Members

Remarks

Port of NumPy 2.4.2's numpy/lib/_index_tricks_impl.py, whose body is self.iter = np.asarray(arr).flat and return self.iter.coords, next(self.iter) — a flatiter walk, i.e. a LOGICAL C-order traversal that honours the array's own strides. So the enumeration order is always C-order regardless of layout (probed: an F-contiguous array enumerates (0,0), (0,1), (1,0), (1,1) — not its memory order), reversed and broadcast views read through their strides, and a 0-d array yields exactly one pair with an EMPTY index (NumPy's ()).

NumSharp's NDArray.flat is a raveled NDArray rather than a flatiter object (it has no coords cursor), so the coordinates come from an odometer advanced in lockstep with the flat position — which is precisely what flatiter.coords is. Indices are long (NumPy's intp), and each step yields a FRESH index array, never a recycled buffer.

Properties

Current

Gets the element in the collection at the current position of the enumerator.

public (long[] index, object value) Current { get; }

Property Value

(long[] index, object value)

The element in the collection at the current position of the enumerator.

Methods

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

public void Dispose()

GetEnumerator()

Returns the enumerator itself — matching NumPy's iter(e) is e, so enumeration shares the single live cursor.

public IEnumerator<(long[] index, object value)> GetEnumerator()

Returns

IEnumerator<(long[] index, object value)>

MoveNext()

Advances the enumerator to the next element of the collection.

public bool MoveNext()

Returns

bool

true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection.

Exceptions

InvalidOperationException

The collection was modified after the enumerator was created.

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