I would like to avoid using swift-algorithms so here's my attempt at handling the brackets with just using Swift. It works for 2D and 3D arrays but brackets for higher dimensions are not captured.
func description<T>(array: [T], shape: [Int]) -> String {
let chunkSize = shape.last ?? 1
let chunks = stride(from: 0, to: numbers.count, by: chunkSize).map {
Array(numbers[$0..<min($0 + chunkSize, numbers.count)])
}
let width = array.map { "\($0)".count }.max() ?? 0
let lines = chunks.map { row in
row.map { element in
(String(repeating: " ", count: width) + element.description).suffix(width)
}.joined(separator: " ")
}
var descr = ""
let dim = shape.count
let lastRow = shape.reduce(1, *) / chunkSize
let lastSubRow = shape.reversed()[1]
for (n, line) in lines.enumerated() {
let n = n + 1
if n == 1 {
// First row brackets
let prepend = String(repeating: "⎡ ", count: dim - 1)
let append = String(repeating: " ⎤", count: dim - 1)
descr += prepend + line + append + "\n"
} else if n == lastRow {
// Last row brackets
let prepend = String(repeating: "⎣ ", count: dim - 1)
let append = String(repeating: " ⎦", count: dim - 1)
descr += prepend + line + append + "\n"
} else if n % lastSubRow == 0 {
// Last row brackets on subarray
let prepend = String(repeating: "⎜ ", count: dim - 2)
let append = String(repeating: " ⎥", count: dim - 2)
descr += prepend + "⎣ " + line + " ⎦" + append + "\n"
} else if n % lastSubRow == 1 {
// First row brackets on subarray
let prepend = String(repeating: "⎜ ", count: dim - 2)
let append = String(repeating: " ⎥", count: dim - 2)
descr += prepend + "⎡ " + line + " ⎤" + append + "\n"
} else {
let prepend = String(repeating:"⎜ ", count: dim - 1)
let append = String(repeating: " ⎥", count: dim - 1)
descr += prepend + line + append + "\n"
}
}
return descr
}
Here's a 2D example:
let numbers: [Float] = [1, 2, 3,
42.8, 5, 6]
let shape = [2, 3]
let d = description(array: numbers, shape: shape)
print(d)
⎡ 1.0 2.0 3.0 ⎤
⎣ 42.8 5.0 6.0 ⎦
Here's a 3D example:
let numbers: [Float] = [1, 2, 3,
4, 5, 6,
7, 8, 9,
10, 11, 12,
13, 14, 15,
16, 17, 18]
let shape = [3, 2, 3]
let d = description(array: numbers, shape: shape)
print(d)
⎡ ⎡ 1.0 2.0 3.0 ⎤ ⎤
⎜ ⎣ 4.0 5.0 6.0 ⎦ ⎥
⎜ ⎡ 7.0 8.0 9.0 ⎤ ⎥
⎜ ⎣ 10.0 11.0 12.0 ⎦ ⎥
⎜ ⎡ 13.0 14.0 15.0 ⎤ ⎥
⎣ ⎣ 16.0 17.0 18.0 ⎦ ⎦
And here is a 4D example. Notice the brackets are not captured for the extra dimension.
let numbers: [Float] = [1, 2, 3, 4,
5, 6, 7, 8,
9, 10, 11, 12,
13, 14, 15, 16,
17, 18, 19, 20,
21, 22, 23, 24,
25, 26, 27, 28,
29, 30, 31, 32,
33, 34, 35, 36,
37, 38, 39, 40,
41, 42, 43, 44,
45, 46, 47, 48]
let shape = [2, 3, 2, 4]
let d = description(array: numbers, shape: shape)
print(d)
⎡ ⎡ ⎡ 1.0 2.0 3.0 4.0 ⎤ ⎤ ⎤
⎜ ⎜ ⎣ 5.0 6.0 7.0 8.0 ⎦ ⎥ ⎥
⎜ ⎜ ⎡ 9.0 10.0 11.0 12.0 ⎤ ⎥ ⎥
⎜ ⎜ ⎣ 13.0 14.0 15.0 16.0 ⎦ ⎥ ⎥
⎜ ⎜ ⎡ 17.0 18.0 19.0 20.0 ⎤ ⎥ ⎥
⎜ ⎜ ⎣ 21.0 22.0 23.0 24.0 ⎦ ⎥ ⎥
⎜ ⎜ ⎡ 25.0 26.0 27.0 28.0 ⎤ ⎥ ⎥
⎜ ⎜ ⎣ 29.0 30.0 31.0 32.0 ⎦ ⎥ ⎥
⎜ ⎜ ⎡ 33.0 34.0 35.0 36.0 ⎤ ⎥ ⎥
⎜ ⎜ ⎣ 37.0 38.0 39.0 40.0 ⎦ ⎥ ⎥
⎜ ⎜ ⎡ 41.0 42.0 43.0 44.0 ⎤ ⎥ ⎥
⎣ ⎣ ⎣ 45.0 46.0 47.0 48.0 ⎦ ⎦ ⎦
Any suggestions on how to print the brackets for higher dimensions without using the swift-algorithms package?
