ak.argcartesian

Defined in awkward.operations.structure on line 3533.

ak.argcartesian(arrays, axis=1, nested=None, parameters=None, with_name=None, highlevel=True, behavior=None)
Parameters

  • arrays (dict or iterable of arrays) – Arrays on which to compute the Cartesian product.

  • axis (int) – The dimension at which this operation is applied. The outermost dimension is 0, followed by 1, etc., and negative values count backward from the innermost: -1 is the innermost dimension, -2 is the next level up, etc.

  • nested (None, True, False, or iterable of str or int) – If None or False, all combinations of elements from the arrays are produced at the same level of nesting; if True, they are grouped in nested lists by combinations that share a common item from each of the arrays; if an iterable of str or int, group common items for a chosen set of keys from the array dict or slots of the array iterable.

  • parameters (None or dict) – Parameters for the new ak.layout.RecordArray node that is created by this operation.

  • with_name (None or str) – Assigns a "__record__" name to the new ak.layout.RecordArray node that is created by this operation (overriding parameters, if necessary).

  • highlevel (bool) – If True, return an ak.Array; otherwise, return a low-level ak.layout.Content subclass.

  • behavior (None or dict) – Custom ak.behavior for the output array, if high-level.

Computes a Cartesian product (i.e. cross product) of data from a set of arrays, like ak.cartesian, but returning integer indexes for ak.Array.__getitem__.

For example, the Cartesian product of

>>> one = ak.Array([1.1, 2.2, 3.3])
>>> two = ak.Array(["a", "b"])

is

>>> ak.to_list(ak.cartesian([one, two], axis=0))
[(1.1, 'a'), (1.1, 'b'), (2.2, 'a'), (2.2, 'b'), (3.3, 'a'), (3.3, 'b')]

But with argcartesian, only the indexes are returned.

>>> ak.to_list(ak.argcartesian([one, two], axis=0))
[(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]

These are the indexes that can select the items that go into the actual Cartesian product.

>>> one_index, two_index = ak.unzip(ak.argcartesian([one, two], axis=0))
>>> one[one_index]
<Array [1.1, 1.1, 2.2, 2.2, 3.3, 3.3] type='6 * float64'>
>>> two[two_index]
<Array ['a', 'b', 'a', 'b', 'a', 'b'] type='6 * string'>

All of the parameters for ak.cartesian apply equally to ak.argcartesian, so see the ak.cartesian documentation for a more complete description.