用VB.NET中的一行代碼替換字符串中的多個字符

Question

使用VB.NET我希望能夠用一行代碼替換字符串中的一系列字符。

即，是這樣的：

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

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

但是，這是行不通的。

下不工作，但我不希望字符串是類級變量：

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 

可以這樣做？

Answer 1

String類有一個替換方法來做到這一點。你可以這樣使用它：

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

Answer 2

如果我正確讀了這個，你試圖從字符串中去掉一個字符列表。這非常適合RegEx。

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

（你需要導入System.Text.RegularExpressions）

Answer 3

我建議喬恩·加洛韋的做法，正則表達式是適當的方法，以及未來開發商將感謝你的:) - 儘管Linq也不是一個難以解決的問題。下面是一些（未經測試）C＃代碼來做到這一點：

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

我懷疑這可能是代碼執行會稍微好一點，然後正則表達式等價的，如果性能是一個問題。

Answer 4

正則表達式的方法是最適合的，但我真的需要說的是：

請，爲維護開發商的愛，不要掛斷上得到這個下降到1行代碼。一個方法調用是你的真正目標，如果你最終只是將一堆調用堆成一行來表示它是單行的，那麼你就是在自己的腳下開槍。

Answer 5

我不相信Bittercode，因爲他說LINQ將超越正則表達式。 所以我做了一個小測試只是爲了確定。如何做到這一點

三個例子：

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 

結果：

所以，for循環與outperformes與string.replace所有其他方法。

因此，我會對字符串對象做一個擴展函數。

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

然後，你可以使用這個功能不錯，可讀取一行：

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

Answer 6

什麼是重複行語句，如果你真的想使用該代碼的最佳方式：

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：如果鍵入：012ALP456HA90BET678輸出將是：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