如何将字符串转换为[[Int]]

func convertStringToIntArray(_ str: String) -> [[Int]] {
    let rows = str.components(separatedBy: ",")
    var result: [[Int]] = []
    
    for row in rows {
        let columns = row.components(separatedBy: " ")
        var intArray: [Int] = []
        
        for column in columns {
            if let num = Int(column) {
                intArray.append(num)
            }
        }
        
        if !intArray.isEmpty {
            result.append(intArray)
        }
    }
    
    return result
}

let str = "1 2 3, 4 5 6, 7 8 9"
let intArray = convertStringToIntArray(str)
print(intArray)

[[1, 2, 3], [4, 5, 6], [7, 8, 9]]