how to replace characters in a array quickly

by

The reason that it spends so much time in that line is because the Contains method loops through the array to look for the character.

Put the characters in a HashSet<char> instead:

private static HashSet<char> badChars =
  new HashSet<char>(new char[] { '\x00', '\x09', '\x0A', '\x10' });

The code to check if the set contains the character looks the same as when looking in the array, but it uses the hash code of the character to look for it instead of looping through all the items in the array.

Alternatively, you could put the characters in a switch, that way the compiler would create an efficient comparison:

switch (buffer[i]]) {
  case '\x00':
  case '\x09':
  case '\x0A':
  case '\x10': buffer[i] = ' '; break;
}

If you have more characters (five or six IIRC), the compiler will actually create a hash table to look up the cases, so that would be similar to using a HashSet.

More Related Contents:

  1. Where is likely the performance bug here? [closed]
  2. Is there any alternate way of avoiding the Foreach loop? [closed]
  3. Getting all types that implement an interface
  4. Most efficient way to concatenate strings?
  5. Tips for optimizing C#/.NET programs [closed]
  6. Why doesn’t .NET/C# optimize for tail-call recursion?
  7. Inline functions in C#?
  8. Is shifting bits faster than multiplying and dividing in Java? .NET? [closed]
  9. Generating permutations of a set (most efficiently)
  10. Does C# optimize the concatenation of string literals?
  11. Why always close Database connection?
  12. File I/O with streams – best memory buffer size
  13. Reducing memory usage of .NET applications?
  14. Fastest method to remove Empty rows and Columns From Excel Files using Interop
  15. What is the real overhead of try/catch in C#?
  16. What is the “cost” of .NET reflection? [duplicate]
  17. Does Interlocked.CompareExchange use a memory barrier?
  18. When is optimization premature? [closed]
  19. Fake-scrolling containers with very many controls
  20. Is the C# compiler smart enough to optimize this code?
  21. Do string literals get optimised by the compiler?
  22. Switch case on type c# [duplicate]
  23. Different ways of adding to Dictionary
  24. Writing FizzBuzz
  25. Micro Optimization of a 4-bucket histogram of a large array or list
  26. How to create an image of a WPF UserControl at runtime
  27. A better way to replace many strings – obfuscation in C#
  28. using static Regex.IsMatch vs creating an instance of Regex
  29. C# Compiler optimization – Unused methods
  30. Method-Chaining in C#

Leave a Comment