如何替换字符串中一个字符的一个实例，然后使用VB语言将输出放置在文本框中

debugcn 发表于 Dev

原件

我们正在尝试仅将“ a”的第一个实例替换为first second third。然后，它将循环并替换第二个实例“ a”为新的生成值，first second third并继续该循环，直到不再有“ a”字符，并且每个“ a”是一个不同的值。但是，输出结果不正确。该代码擦除了最后一个“ a”之前的所有字符，然后替换了最后一个“ a”。

    Dim message As String
    Dim start As Integer = 1
    Dim letterfinder As String
    Dim timesLooped As Integer = 1
    Dim length As Integer

    Dim first As Integer
    Dim second As Integer
    Dim third As Integer
    Dim count As Integer = 1

    message = inputBox.Text
    length = Len(message)
    timesLooped = 0
  While length > timesLooped
        Dim random As New Random
        letterfinder = Mid$(message, start, 1)
        If letterfinder = "a" Then
            first = random.Next(3, 9)
            second = 1 \ first
            third = 1 - second
            outputBox.Text = Replace(message, letterfinder, first & second & third, [start], [count])
        End If
        timesLooped = timesLooped + 1
        start = start + 1
    End While

普萨·庞杰伦德拉普

您的output.text框仅显示最终结果（临时更改发生得太快而看不到）。添加一个列表框以查看进度：

   If letterfinder = "a" Then
       first = random.Next(3, 9)
       second = 1 \ first
       third = 1 - second

       Dim res As String = Replace(message, letterfinder, _
                   first & second & third, [start], [count])
       txtOutput.Text = res
       ListBox1.Items.Add(timesLooped.ToString & vbTab & res)
   End If


Replace(message, "a", first & second & third, [start], [count])

在开始时返回一个子串STARTING ...它不会替代并返回整个东西。的第二遍结果abaca为701ca。一个列表框将向您显示。
对于ababfdsfac替换，结果为：

第701章
第801章
301c

您只能从当前的起始值获得零件

编辑

这是一个执行您想要的操作的循环。我使用VB6类型的方法，因为OP代码比.Net的样式更多。

    Dim first As Integer
    Dim result As String = ""
    Dim random As New Random
    ListBox1.Items.Clear()

    For n As Integer = 1 To Len(message)
        If Mid$(message, n, 1) = "a" Then

            first = random.Next(3, 9)
            result = result & CStr(first)
            result = result & CStr(1 \ first)               ' always 0
            result = result & CStr(1 - (1 \ first))         ' always 1
        Else
            result = result & Mid$(message, n, 1)

        End If

        txtOutput.Text = result
        ListBox1.Items.Add(result)                  ' post interim results
    Next

高温超导

本文收集自互联网，转载请注明来源。

如有侵权，请联系[email protected] 删除。