在一个字符串中计算特定字符出现的次数

使用：

Function fNbrStrInStr(strin As Variant, strToCount As String)
    fNbrStrInStr = UBound(Split(strin, strToCount)) - LBound(Split(strin, strToCount))
End Function

我使用strin作为变量来处理非常长的文本。拆分可以基于零或一，具体取决于用户设置，减去它可以确保正确的计数。

我没有包含一个测试来检查strcount是否比strin更长，以保持代码简洁。

    Function inStC(myInput As String, Search As String, Optional myCompareMethod As Long = CompareMethod.Text) As Long
        If InStr(1, myInput, Search, myCompareMethod) = 0 Then Return 0
        Return UBound(Split(myInput, Search,, myCompareMethod))
    End Function

我喜欢的一件事是它使用紧凑的例子。

str="the little red hen"
count=inStC(str,"e") 'count should equal 4
count=inStC(str,"t") 'count should equal 3

在这里，我想推荐我的inStB函数，它不仅可以返回字符串的计数，而且如果搜索字符串存在，它将简单地返回一个布尔值。我经常需要使用这个函数，这使得我的代码更加简洁。

Function inStB(myInput As String, Search As String, Optional Start As Long = 1, Optional myCompareMethod As Long = CompareMethod.Text) As Boolean
    If InStr(Start, myInput, Search, myCompareMethod) > 0 Then Return True
    Return False
End Function

    ' Trying to find the amount of "." in the text
    ' if txtName looks like "hi...hi" then intdots will = 3
    Dim test As String = txtName.Text
    Dim intdots As Integer = 0
    For i = 1 To test.Length
        Dim inta As Integer = 0 + 1
        Dim stra As String = test.Substring(inta)
        If stra = "." Then
            intdots = intdots + 1
        End If
    Next
    txttest.text = intdots

Private Sub Data_KeyPress(sender As Object, e As KeyPressEventArgs) Handles Data.KeyPress
    If Not IsNumeric(e.KeyChar) And Not e.KeyChar = ChrW(Keys.Back) And Not e.KeyChar = "." Then
        e.Handled = True
    Else
        If e.KeyChar = "." And Data.Text.ToCharArray().Count(Function(c) c = ".") > 0 Then
            e.Handled = True
        End If
    End If
End Sub

使用：

Dim a
inputString = InputBox("Enter String", "Enter Value", "")

MyString = UCase(inputString)

MsgBox MyString

Dim stringLength

stringLength = Len(MyString)

Dim temp

output = ""

i = 1
Do
    temp = Mid(MyString, i, 1)

    MsgBox temp & i

    CharacterCount = len(MyString) - len(Replace(MyString, temp, ""))

    MyString = Replace(MyString, temp, "")

    output = output & temp & ": " & CharacterCount & vbNewline

Loop While MyString <> ""

MsgBox output

        Dim str As String = "the little red hen"

        Dim total As Int32

        Dim Target As String = "e"
        Dim Temp As Int32
        Dim Temp2 As Int32 = -1
Line50:
        Temp = str.IndexOf(Target, Temp2 + 1)
        Temp2 = Temp
        If Temp <> -1 Then

            ' Means there is a target there
            total = total + 1
            GoTo Line50
        End If

        MessageBox.Show(CStr(total))

现在，这是一个解决OP问题的方便函数：

    Public Function CountOccurrence(ByVal YourStringToCountOccurrence As String, ByVal TargetSingleCharacterToCount As String) As Int32
        Dim total As Int32

        Dim Temp As Int32
        Dim Temp2 As Int32 = -1
Line50:
        Temp = YourStringToCountOccurrence.IndexOf(TargetSingleCharacterToCount, Temp2 + 1)
        Temp2 = Temp
        If Temp <> -1 Then

            ' Means there is a target there
            total = total + 1
            GoTo Line50
        Else
            Return total
        End If
    End Function

使用该函数的示例：

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Dim str As String = "the little red hen"

    MessageBox.Show(CStr(CountOccurrence(str, "e")))
    ' It will return 4
End Sub