如何在 Rust 中简洁地定义多维 Vec？

Question

When initializing a multidimensional Vec in Rust, I can use the vec! -macro like this:

vec![vec![0; 100]; 200]

However, this gets messy for Vec s of higher dimensions. Currently, I am using this:

vec![vec![vec![vec![vec![vec![vec![vec![0; N-1]; N-1]; N-1]; N-1]; 2]; 2]; 2]; 2]

This is not very concise, and also the order in which the dimensions are written is reverse to the indexing order. Is there a more concise way to do this? I am looking for something like

vec![0; 2, 2, 2, 2, N-1, N-1, N-1, N-1]

Answer 1

The ndarray crate allows you to have an N-dimensional array. For anything above 6 dimensions, you can use the ArrayD type. You can create a dynamic dymension using IxDyn - documentation with examples .

Example for a 7x7x7...x7 array initialization and element access:

    let mut array_7d = ArrayD::<f64>::zeros(IxDyn(&[7, 7, 7, 7, 7, 7, 7, 7]));
    let index = IxDyn(&[0, 0, 0, 0, 0, 0, 0, 0]);
    array_7d[&index] = 1.0;