CODEWITHSUNDEEP
c#string.net-3.5trim
makerofthings7
makerofthings7

Reputation: 61463

Unexpected results with "TrimEnd()" ... results are randomly too greedy

I'm getting inconsistent results with TrimEnd() under .NET 3.5. TrimEnd seems so simple to use, is there something I'm doing wrong here or is this a bug

Success case

  var foundvalue = "hosted.local.chatter.com";
  Console.WriteLine(foundvalue.TrimEnd(".chatter.com".ToCharArray()));
  // Result is "hosted.local" which is expected.

Failure case

 var foundvalue = "hosted.local.chattermailcom";
 Console.WriteLine(foundvalue.TrimEnd(".chattermailcom".ToCharArray()));
 // Result is "hosted" which is incorrect

Upvotes: 1

Views: 258

Answers (5)

Jeppe Stig Nielsen
Jeppe Stig Nielsen

Reputation: 61952

Maybe you could write your own method for that:

public static class Extensions
{
  public static string RemoveEnd(this string strBefore, string substringToRemove)
  {
    if (!strBefore.EndsWith(substringToRemove))
      return strBefore;

    return strBefore.Remove(strBefore.Length - substringToRemove.Length);
  }
}

Upvotes: 4

loopedcode
loopedcode

Reputation: 4893

TrimEnd is not designed to strip a string off. The word "local" contains all characters that are in your trimEnd chars ("chattermailcom" -> includes l, o, c, a, and l). You are getting expected behavior of trimEnd.

String.TrimEnd Method (MSDN):

The TrimEnd method removes from the current string all trailing characters that are in the trimChars parameter. The trim operation stops when the first character that is not in trimChars is encountered at the end of the string. For example, if the current string is "123abc456xyz789" and trimChars contains the digits from "1" through "9", the TrimEnd method returns "123abc456xyz".

Upvotes: 1

Servy
Servy

Reputation: 203817

You aren't removing the exact string, ".chattermailcom" from the end, you're removing each of the characters, '.', 'c', 'a', 't', 'e', 'r', etc. from the end of the string. ".chattermailcom" happens to have all of the letters in local, but ".chatter.com" doesn't (the key letter there being the l).

If you want to remove the entire string from the end consider using EndsWith to do the check, and then substring if it's true.

You could also consider avoiding the string manipulation entirely and using the URI class; it could parse the entire URL for you and return the various components.

Upvotes: 11

Gene
Gene

Reputation: 4232

As per documentation, TrimEnd removes all characters from the end of the string which are in the array you've passed. For the second case, the "d" is not part of the array so the method will stop here.

Upvotes: 6

SomebodyYouKnow
SomebodyYouKnow

Reputation: 181

Why does that surprise you? TrimEnd takes an array of characters to remove from the end. You tell it to remove all '.', 'c', 'h', 'a', 't' and so on.. And exactly why you tell it to remove it all characters within the string ".local.", they will be removed. Please read again what TrimEnd() does.

Upvotes: 2

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