加速函數反轉字符串

Question

我正在使用此函數來反轉文本，但我有一個小問題的速度。 進行測試我有130,000個字符的文本，大約需要10秒。是否有可能加快速度？這個問題是不是C＃不同，因爲它是一個vb.net

Function ReverseString(ByRef strString As String) As String 
     Dim NextChr, TempString As String, StringLength, Count As Integer, NewString As String = Nothing 

     TempString = strString 
     StringLength = Len(TempString) 
     Do While Count <= StringLength 
      Count = Count + 1 
      NextChr = Mid(TempString, Count, 1) 
      NewString = NextChr & NewString 
     Loop 
     ReverseString = NewString 
End Function 

Answer 1

試試這個：

Function Reverse(ByVal value As String) As String 
    ' Convert to char array. 
    Dim arr() As Char = value.ToCharArray() 
    ' Use Array.Reverse function. 
    Array.Reverse(arr) 
    ' Construct new string. 
    Return New String(arr) 
    End Function 

來源：dot net perls

Answer 2

也許沿http://msdn.microsoft.com/en-us/library/e462ax87(v=vs.90).aspx線的東西？ 在VB：

Dim TestString As String = "ABCDEFG" 
' Returns "GFEDCBA". 
Dim revString As String = StrReverse(TestString) 

Answer 3

Function ReverseString(ByRef strString As String) As String 
    Dim charArray As Char() = strString.ToCharArray() 
    Array.Reverse(charArray) 
    Dim strReversed As New String(charArray) 
    ReverseString = strReversed 
End Function 

Answer 4

我想你的字符串轉換爲字符數組，然後只需調用Array.Reverse。

我剛試過這個，它運行在：0.862秒，字符串有26,673,152個字符。當然，我正在一臺極其快速的個人電腦上運行，但仍然存在。

Answer 5

正如在其他的答案說 - 最好是使用特殊的功能是：StrReverse

但是，如果你想擁有自己的功能，你可以用這個，應該是更快：

Function ReverseString(ByRef strString As String) As String 
    Dim builder As New System.Text.StringBuilder(strString.Length) 
    Dim index As Integer = strString.Length - 1 
    While index >= 0 
     builder.Append(strString.Chars(index)) 
     index = index - 1 
    End While 
    ReverseString = builder.ToString 
End Function