Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        DIC_RES(1)
    End Sub
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        DIC_RES(0)
    End Sub
    Sub DIC_RES(ByVal ST As Integer)
        RichTextBox1.Text = ""  '清空文本框
        '定义二维数组
        Dim arr(,) As Object = {{"A", 1}, {"B", 2}, {"P", 3}, {"D", 4}, {"P", 5}, {"A", 6}, {"R", 7}, {"C", 8}, {"D", 9}, {"E", 10}}
        '定义一个字典
        Dim dic As Dictionary(Of String, String) = New Dictionary(Of String, String)
        '遍历数组取数
        For i As Integer = 0 To UBound(arr, 1)
            If ST = 1 Then  '判断状态为1时执行计数否则执行求和
                If dic.ContainsKey(arr(i, 0)) Then  '判断key是否存在
                    dic(arr(i, 0)) += 1  '相同加一
                    dic(arr(i, 0)) = 1   '否则保持唯一
                End If
                If dic.ContainsKey(arr(i, 0)) Then  '判断key是否存在
                    dic(arr(i, 0)) = dic(arr(i, 0)) + arr(i, 1)  '相同的keys值求和
                    dic(arr(i, 0)) = arr(i, 1)  '否则变
                End If
            End If
        For Each ch As String In dic.Keys  '遍历取出统计后的数据
            If ST = 1 Then
                RichTextBox1.AppendText(ch & "出现" & dic(ch) & "次" & vbCrLf)
                RichTextBox1.AppendText(ch & "的和为" & dic(ch) & vbCrLf)