question

[tuoeg]

PyReadonlyArray2 how to convert to vec<vec>? thanks

[adamreichold]

I think the easiest way to achieve this is to use ndarray's rows or Columns iterators and collect those, e.g.

fn array2_to_vec2(array: PyReadonlyArray2<f64>) -> Vec<Vec<f64>> {
    array
        .as_array()
        .rows()
        .into_iter()
        .map(|row| row.iter().copied().collect::<Vec<_>>())
        .collect::<Vec<_>>()
}

But that said, this is an usual conversion as the resulting memory layout is relatively inefficient compared to store the two-dimensional array in a single allocation. Maybe you could expand a little on why you need Vec<Vec<_>> and we can find a way to reduce the number of separate allocations?