Question

我需要使用数组和字符串。该程序应该只搜索用户将输入的1个号码（0-9）。这是我的代码如下。它使用一个数组来获取一个随机数，并且它正在测试每个数字的出现次数。但是它没有用，但我不需要它来测试每个数字。

程序必须只测试用户请求的1号码。因此，如果生成的随机数是...'7417'，并且用户用户选择了'7'，那么程序将报告已经有两个七位数。我将使用文本框'txtEnter'来获取要搜索的用户号码。谁能帮我？谢谢！

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
  Randomize()
  Dim ArrayNum(1) As Integer
  ArrayNum(0) = Int(Rnd() * 100000)

  lblDisplayNumber.Text = ArrayNum(0)

  Dim num As Integer
  txtEnter.Text = num
  Dim counts = From c In num.ToString()
               Group By c Into Group
               Select DigitGroup = New With {.Count = Group.Count(),
                                             .Digit = c, .Group = Group}
               Order By DigitGroup.Count Descending
               Select String.Format("There are {0} number {1}'s found.",
                                     DigitGroup.Count, DigitGroup.Digit)
  Dim message = String.Join(Environment.NewLine, counts)
End Sub

Answer 1

如果您想使用Linq，它简短易读：

Dim counts = From c In num.ToString()
             Group By c Into Group
             Select DigitGroup = New With {.Count = Group.Count(), .Digit = c, .Group = Group }
             Order By DigitGroup.Count Descending
             Select String.Format("There are {0} number {1}'s found.",
                                   DigitGroup.Count, DigitGroup.Digit)
Dim message = String.Join(Environment.NewLine, counts)

更新：这是一个完整的示例，显示输入的数字和摘要的结果：

Dim rnd As New Random()
Dim randomInt = rnd.Next(0, 100000)
lblDisplayNumber.Text = randomInt.ToString()

Dim num As Integer
If Int32.TryParse(txtEnter.Text, num) AndAlso num >= 0 AndAlso num < 10 Then
    Dim counts = From c In randomInt.ToString()
             Group By c Into Group
             Select DigitGroup = New With {.Count = Group.Count(), .Digit = c, .Group = Group}
             Order By DigitGroup.Count Descending, DigitGroup.Digit
    Dim numCount = counts.FirstOrDefault(Function(grp) grp.Digit.ToString() = num.ToString())
    If numCount IsNot Nothing Then
        Dim numMessage = String.Format("There are {0} number {1}'s found.", numCount.Count, num)
        MessageBox.Show(numMessage)
    Else
        MessageBox.Show("Number does not contain " & num)
    End If
    Dim summaryCount = From grp In counts
                       Select String.Format("There are {0} number {1}'s found.", grp.Count, grp.Digit)
    Dim summaryMessage = String.Join(Environment.NewLine, summaryCount)
    MessageBox.Show("Summary:" & Environment.NewLine & summaryMessage)
Else
    MessageBox.Show("Please enter a number between 0 and 9.")
End If

Answer 2

您的代码有几个问题，但要直接回答缺少的问题：

您应该将随机数转换为字符串

 Number= Int(Rnd() * 100000) 
 NumberString = Number.ToString()

将该字符串转换为字符数组

 DigitArray = NumberString.ToCharArray()

然后循环遍历数组的所有字符，并将每个字符c转换回整数

 For Each c As Char In DigitArray
     num = c - "0"C`

然后使用num作为counts数组的索引

     count(num)+=1

而不是那种可怕的switch陈述。我让你弄清楚这些变量的正确Dim语句。

Answer 3

如果您只需要查找输入的数字在随机数字中的次数，前面介绍的解决方案似乎有点复杂。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    ' create the data
    Dim nDigits As Integer = 5
    Dim digits(nDigits - 1) As String
    For i = 0 To nDigits - 1
        digits(i) = CInt(Rnd() * 10).ToString
    Next

    ' show the data
    TextBox1.Text = String.Join("", digits)

    Dim inp = InputBox("Enter a number from 0 to 9")

    ' count the occurrences of the entered number
    Dim nFound = digits.Count(Function(d) d = inp)

    MsgBox(String.Format("There are {0} occurrences of {1}.", nFound, inp))

End Sub

Visual Basic - 从随机数组中计算数字的出现次数

3 个答案: