NumPy

numpy.nested_iters

numpy.nested_iters()

Create nditers for use in nested loops

Create a tuple of nditer objects which iterate in nested loops over different axes of the op argument. The first iterator is used in the outermost loop, the last in the innermost loop. Advancing one will change the subsequent iterators to point at its new element.

Parameters
opndarray or sequence of array_like

The array(s) to iterate over.

axeslist of list of int

Each item is used as an “op_axes” argument to an nditer

flags, op_flags, op_dtypes, order, casting, buffersize (optional)

See nditer parameters of the same name

Returns
iterstuple of nditer

An nditer for each item in axes, outermost first

See also

nditer

Examples

Basic usage. Note how y is the “flattened” version of [a[:, 0, :], a[:, 1, 0], a[:, 2, :]] since we specified the first iter’s axes as [1]

>>> a = np.arange(12).reshape(2, 3, 2)
>>> i, j = np.nested_iters(a, [[1], [0, 2]], flags=["multi_index"])
>>> for x in i:
...      print(i.multi_index)
...      for y in j:
...          print('', j.multi_index, y)
(0,)
 (0, 0) 0
 (0, 1) 1
 (1, 0) 6
 (1, 1) 7
(1,)
 (0, 0) 2
 (0, 1) 3
 (1, 0) 8
 (1, 1) 9
(2,)
 (0, 0) 4
 (0, 1) 5
 (1, 0) 10
 (1, 1) 11

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