Question

我正在尝试合并2个数组，
SELECT JSON_EXTRACT_SCALAR(raw_json , "$[\"Type\"]") as parsed_type FROM `table` LIMIT 1000
        .tooltip .arrow:before { border-top-color: #008ec3 !important; } .tooltip .tooltip-inner { background-color: #008ec3; }
        Dim arr1(3) As String
        arr1(0) = "a"
        arr1(1) = "b"

arr1(2) = "c"
        arr1(3) = "d"
        Dim arr2(4) As String
        arr2(0) = "a"
        arr2(1) = "x"
        arr2(2) = "x"

arr2(3) = "b"
arr2(4) = "z"

Dim arr3 As String()

合并后会发生的情况是仅打印单个值

ReDim arr3(UBound(arr1) + UBound(arr2) + 1)
        Dim i As Integer For i = 0 To UBound(arr1) arr3(i * 2) = arr1(i) arr3(i * 2 + 1) = arr2(i) Label8.Text = String.Join(",", arr3)
        Dim r = From s In arr3         Group By s Into Group, Count()
        Where Count = 1
            Select s
        Order By s

购买它只打印Label9.Text = String.Join(",", r)，在合并两个应该为Next i的数组后，它应该打印两个数组中出现一次的所有单个元素。我的代码有什么问题？谢谢。

Answer 1

由于两个源数组可以具有不同的上限，因此您将不得不使用两者中的较高者进行迭代，并确保不要访问较短数组边界之外的索引

Dim arr1() As String = {"a", "b", "c", "d"}
Dim arr2() As String = {"a", "x", "x", "b", "z"}

Dim arr3(arr1.Length + arr2.Length - 1) As String

Dim iDestination As Integer = 0
For i As Integer = 0 To Math.Max(UBound(arr1), UBound(arr2))
    If i <= UBound(arr1) Then
        arr3(iDestination) = arr1(i)
        iDestination += 1
    End If
    If i <= UBound(arr2) Then
        arr3(iDestination) = arr2(i)
        iDestination += 1
    End If
Next

这与您进行的结果交错。

如果不需要交织并且您只对结果感兴趣（而不是对算法感兴趣），则可以执行以下操作：

Dim arr1() As String = {"a", "b", "c", "d"}
Dim arr2() As String = {"a", "x", "x", "b", "z"}

Dim r = From s In arr1.Concat(arr2)
    Group By s Into Group, Count()
    Where Count = 1 Select s
    Order By s

这将返回在arr1或arr2中恰好出现一次的元素。

Answer 2

使用Array.CopyTo

的另一种方法

Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
    Dim arr1(3) As String
    arr1(0) = "a"
    arr1(1) = "b"
    arr1(2) = "c"
    arr1(3) = "d"

    Dim arr2(4) As String
    arr2(0) = "a"
    arr2(1) = "x"
    arr2(2) = "x"
    arr2(3) = "b"
    arr2(4) = "z"

    Dim arr3 As String()
    ReDim arr3(arr1.Length + arr2.Length)

    arr1.CopyTo(arr3, 0)
    arr2.CopyTo(arr3, arr1.Length)

    For Each s As String In arr3
        Debug.Print(s)
    Next
End Sub

新加入的数组缺少元素-VB

2 个答案: