在VB.NET的一行代码中替换字符串中的多个字符

Question

使用 VB.NET，我希望能够在一行代码中替换字符串中的一系列字符。

例如，类似：

Dim charsToReplace as string = "acegi"
Dim stringToBeReplaced as string = "abcdefghijklmnop"

charsToReplace.ToArray().ForEach(Function (c) stringTobeReplaced = stringTobeReplaced.Replace(c, ""))

但是，这不起作用。

以下确实有效，但我不希望字符串成为类级别变量：

 Sub Main()
    Dim toReplace As String = "acegikmoq"

    Console.WriteLine(mainString)
    Dim chars As List(Of Char) = toReplace.ToList()
    chars.ForEach(AddressOf replaceVal)

    Console.WriteLine(mainString)
    Console.ReadLine()
End Sub

Dim mainString As String = "this is my string that has values in it that I am going to quickly replace all of..."

Sub replaceVal(ByVal c As Char)
    mainString = mainString.Replace(c, "")
End Sub

这个可以吗？

Answer 1

String 类有一个替换方法来执行此操作。你可以这样使用它：

YourString = YourString.Replace("OldValue", "NewValue")

Answer 2

如果我没看错，您是在尝试从字符串中删除字符列表。这非常适合 RegEx。

Console.WriteLine(Regex.Replace("abcdefghijklmnop", "[acegi]", string.Empty))

（您需要导入 System.Text.RegularExpressions）

Answer 3

我推荐 Jon Galloway 的方法，正则表达式是合适的方法，未来的开发人员会感谢你的 :) - 尽管使用 Linq 解决它也不是一个困难的问题。以下是一些（未经测试的）C# 代码：

string stringToBeReplaced = "abcdefghijklmnop";
string charsToReplace = "acegi";
stringToBeReplaced = new String(stringToBeReplaced.Where(c => !charsToReplace.Any(rc => c == rc)).ToArray());

如果性能有问题，我怀疑这段代码的性能可能会比等效的正则表达式稍好一些。

Answer 4

RegEx 方法是最合适的，但我真正需要说的是：

出于对维护开发人员的热爱，请不要急于将其缩减为 1 行代码。一个方法调用是您的真正目标，如果您最终只是将一堆调用堆积到 1 行中说它是单行，那么您就是在自取其辱。

Answer 5

我不相信 Bittercode，因为他说 LINQ 会胜过正则表达式。 所以我做了一个小测试来确定。

如何做到这一点的三个例子：

Dim _invalidChars As Char() = New Char() {"j"c, "a"c, "n"c}
Dim _textToStrip As String = "The quick brown fox jumps over the lazy dog"

Private Sub btnStripInvalidCharsLINQ_Click(sender As System.Object, e As System.EventArgs) Handles btnStripInvalidCharsLINQ.Click
    Dim stripped As String = String.Empty
    Dim sw As Stopwatch = Stopwatch.StartNew
    For i As Integer = 0 To 10000
        stripped = _textToStrip.Where(Function(c As Char) Not _invalidChars.Contains(c)).ToArray
    Next
   sw.Stop()

    lblStripInvalidCharsLINQ.Text = _stripped & " - in " & sw.Elapsed.TotalMilliseconds & " ms"
End Sub

Private Sub btnStripInvalidCharsFOR_Click(sender As System.Object, e As System.EventArgs) Handles btnStripInvalidCharsFOR.Click
    Dim stripped As String = String.Empty
    Dim sw As Stopwatch = Stopwatch.StartNew
    stripped = _textToStrip
    For i As Integer = 0 To 10000
        For Each c As Char In _invalidChars
            stripped = stripped.Replace(c, "")
        Next
    Next
    sw.Stop()

    lblStipInvalidcharsFor.Text = stripped & " - in " & sw.Elapsed.TotalMilliseconds & " ms"
End Sub

Private Sub btnStripInvalidCharsREGEX_Click(sender As System.Object, e As System.EventArgs) Handles btnStripInvalidCharsREGEX.Click
    Dim stripped As String = String.Empty
    Dim sw As Stopwatch = Stopwatch.StartNew
    For i As Integer = 0 To 10000
        stripped = Regex.Replace(_textToStrip, "[" & New String(_invalidChars) & "]", String.Empty)
    Next
    sw.Stop()

    lblStripInvalidCharsRegex.Text = stripped & " - in " & sw.Elapsed.TotalMilliseconds & " ms"
End Sub

结果：

因此，带有 string.replace 的 for 循环优于所有其他方法。

因此，我将为字符串对象创建一个扩展函数。

Module StringExtensions
<Extension()> _
Public Function ReplaceAll(ByVal InputValue As String, ByVal chars As Char(), replaceWith As Char) As String
    Dim ret As String = InputValue
    For Each c As Char In chars
        ret = ret.Replace(c, replaceWith)
    Next
    Return ret
End Function

那么你就可以在一行中很好地和可读地使用这个函数了：

_textToStrip.ReplaceAll(_invalidChars, CChar(String.Empty))

Answer 6

如果您真的想使用该代码，重复该行语句的最佳方法是什么：

Sub Main() 

    Dim myString As String = Nothing
    Dim finalString As String = Nothing
    Console.Write("Please enter a string: ") 'your free to put anything
    myString = Console.ReadLine()
    finalString = myString.Replace("0", "")
    myString = finalString
    finalString = myString.Replace("1", "")
    myString = finalString
    finalString = myString.Replace("2", "")
    myString = finalString
    finalString = myString.Replace("3", "")
    myString = finalString
    finalString = myString.Replace("4", "")
    myString = finalString
    finalString = myString.Replace("5", "")
    myString = finalString
    finalString = myString.Replace("6", "")
    myString = finalString
    finalString = myString.Replace("7", "")
    myString = finalString
    finalString = myString.Replace("8", "")
    myString = finalString
    finalString = myString.Replace("9", "")
    Console.WriteLine(finalString)
    Console.ReadLine()
End Sub

例如：如果您输入：012ALP456HA90BET678，输出将是：ALPHABET。

Answer 7

Public Function SuperReplace(ByRef field As String, ByVal ReplaceString As String) As String
  ' Size this as big as you need... it is zero-based by default'
  Dim ReplaceArray(4) As String

  'Fill each element with the character you need to replace'

  ReplaceArray(0) = "WARD NUMBER "
  ReplaceArray(1) = "WN "
  ReplaceArray(2) = "WARD NO "
  ReplaceArray(3) = "WARD-"
  ReplaceArray(4) = "WARD "

  Dim i As Integer
  For i = LBound(ReplaceArray) To UBound(ReplaceArray)
    field = Replace(field, ReplaceArray(i), ReplaceString)
    Next i
  SuperReplace = field
End Function

Answer 8

Private Sub cmdTest_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdTest.Click
    Dim s As String = "México Juárez índice recúrso dirección"
    Dim arr() As String = {"á", "é", "í", "ó", "ú", "Ñ", "ñ"}
    Dim rep() As String = {"a", "e", "i", "o", "u", "N", "n"}
    Dim i As Integer = Nothing

    For i = 0 To UBound(arr)
        s = Replace(s, arr(i), rep(i))
    Next

    MsgBox(s)

End Sub